I would suggest you may do better to put your money into building up the 350 block you own.

Simply swapping a 383 for your 350 may not get you the powerful engine you wish for. It may be a fuel guzzling disappointment and cost you far more than expected.

A 350 SBC can be built to 375-400HP by a competent engine shop. That is plenty for cruising with the occasional tire roasting burnout.

 

Yeah, I've had this thought also. I have a suspicion that the engine is a numbers matching for this car, but not sure how I can find that out🤔

 

Thinking of installing a 383 blueprint engine in my 68. It has a lazy/weak 350 in it now with 1406 edelbrock carb, edelbrock intake manifold and headers. I therefor have a few questions regarding the upgrade.

1. How much hp does a stock TH350 handle? And whats the best upgrade option?
2. How much hp does a stock open diff 8.2 rear end handle?

I know these two questions depends on the driving style, but I'm thinking of mainly just cruising, doing some light pulls now and then.

3: Could I use the same carb and intake manifold on a longblock 383, or should I go for something better?

And last but not least:
How much more fuel should I expect a 383 will use compared to my 350 when cruising/driving normally?

(In Norway were I'm located, the 98 octane fuel costs up to 10.75$ per gallon😬)

since you asked, I would rebuild the 350, but first find out the cc/compression ratio/camshaft specs/crankshaft specs. A lot of touted 350 engines are 307 or 327. Find out what you actually have first. If it is a 350, I would rebuild it.
The trans and rear will handle it fine-provided they are in decent shape.

 

since you asked, I would rebuild the 350, but first find out the cc/compression ratio/camshaft specs/crankshaft specs. A lot of touted 350 engines are 307 or 327. Find out what you actually have first. If it is a 350, I would rebuild it.
The trans and rear will handle it fine-provided they are in decent shape.

I have only been told that the engine is a 350 and has been bored to 355, but I have a suspicion it's a 327. Based on the power in it. I think it has around 200hp.

 

When I went from a carburetor to fuel injection, upgraded from a Turbo 350 to a 700R4 transmission, 3:55 rear end, my fuel mileage doubled with my 383. I am now getting mid 20's for mileage on the freeway.

 

And last but not least:
How much more fuel should I expect a 383 will use compared to my 350 when cruising/driving normally?

I can tell you my experience going from a 350 to a 383. I drive my 67 Camaro to and from work every day. With the 350 I could make the trip for 2 weeks on a tank of gas. I expected the 383 to cost me more in fuel ... However I had a buddy of mine telling me it will probably save me on fuel since I am doing city street driving.

Well guess what? My buddy was right. During the summer I was getting to and from work for a full 3 weeks on a tank of gas. Winter has hindered it a bit do to (I believe) using the choke and high idle speed for a portion of the trip. I bought gas on the 12th of January and just filled the tank day before yesterday (28th). I made another short trip along with trips to and from work on this last tank. So about 2.5 weeks for winter driving.

Cruise speed on our city streets has me at about 1,500 RPM if I want to be in 4th gear. The 350 was not at all happy with that.

The new 383 does not care one bit about pulling along at 1,500 RPM. The vastly improved low end torque proved my buddy to be correct.

Disclaimer: I have no idea how this will compare to your situation, but that is real life feedback on your question from the streets of Las Vegas.

I could add: I built my 383 and used the cam and heads I previously ran in the 350. Timing on the cam is advanced 2° and static compression is actually lower than with the 350 (dropped from about 9.5 to 9.25) however dynamic CR is still very nicely in the range I wanted for a street engine. Being a street driven car the choice of parts available had me choosing between possibly erroring too high (for my liking) on the high side or settling for a bit less than my ideal 9.5. My hydraulic roller cam is fairly mild and does not bleed off a lot of compression.

Also, My Dart heads have 200cc intake runners. For the way my 350 was built and used those are probably a bit too large. The extra 30 plus cubic inches makes better use of those runners.

 

I can tell you my experience going from a 350 to a 383. I drive my 67 Camaro to and from work every day. With the 350 I could make the trip for 2 weeks on a tank of gas. I expected the 383 to cost me more in fuel ... However I had a buddy of mine telling me it will probably save me on fuel since I am doing city street driving.

Well guess what? My buddy was right. During the summer I was getting to and from work for a full 3 weeks on a tank of gas. Winter has hindered it a bit do to (I believe) using the choke and high idle speed for a portion of the trip. I bought gas on the 12th of January and just filled the tank day before yesterday (28th). I made another short trip along with trips to and from work on this last tank. So about 2.5 weeks for winter driving.

Cruise speed on our city streets has me at about 1,500 RPM if I want to be in 4th gear. The 350 was not at all happy with that.

The new 383 does not care one bit about pulling along at 1,500 RPM. The vastly improved low end torque proved my buddy to be correct.

Disclaimer: I have no idea how this will compare to your situation, but that is real life feedback on your question from the streets of Las Vegas.

I have always thought, if I make more power lower in the rpm range then use less rpms, then less gas? Sounds like that's semi logical. Glad you experienced the improvement in mileage.

 

OP

I went from an original 210 hp 327 I had a Edelbrock Performer intake on and 1406 carb to a BPE 355 making 411hp/413tq, headers, with a TH350 and 8.2" 3:08 posi rear end. I di use the Edelbrock Air Gap intake but kept the 1406 carb

Your BPE 383 will make more HP & TQ and the specs will note to use a 2000-2400 RPM stall torque converter. I have the HUGHES 2000HD TC.

I still get the same 15mpg my 327 did but the HP and performance gain is huge. My TH350 has been rebuilt previously and no issue with it or rear end.

I did buy the 1406 calibration kit and wound up going 1 jet size larger for primary & secondary's.

IMHO for the cost and performance vs a rebuild the BPE is a better choice. 1 piece RMS, 4 bolt mains, modern heads, full roller cam and a 3 yr/50k mi warranty and the motor has been run on a dino.

 

Unless it's an SS, Z28 or other car the numbers match doesn't do much for added value.

Drop in a new 383 and store the OEM engine if it is, in fact, the born with engine.

 

BPE 383 dressed long block w/carb is under $6K (US dollar) and is rated at 436hp/443tq. IMO that is a pretty big bang for the buck. You would be hard pressed to get equal performance out of a 350. If that is the budget you are looking at, the BPE is a good value and is very popular right now. That power in a 1st gen Camaro is plenty enough to have street fun with. A long block is less. Carb recommendations are all over the place on the internet for a 383, anywhere from 650 to 750 CFM are the most common. Dual plane intake is best for the street, good power in lower RPMs.

If your budget is a little more, there are other builders to consider. If your budget is less, rebuild what you have. Your heads will have the largest impact on the power potential of a rebuild.

remember... "there is no replacement for displacement"

I have an older BPE 383 in my 67. It is a good engine. You wont be disappointed if you go with one. I cannot comment on fuel mileage, I have no data.

 

I believe the fuel mileage data is reflected on your credit card statement. 😆😆

 

A stock TH350 may not last long behind 436hp/443tq. Can you get a performance rebuild in your area? If not, a tranny built for your hp rating would be a good upgrade to start with, easier to do it all at the same time. If you upgrade to a higher stall converter make sure to add a cooler.

Your rear end should be ok so long as you are running street tires. Without a posi unit you are going to be replacing that one rear tire a lot!

 

Yeah, actually there's plenty of transmission builders here in Norway. But I've also been thinking of building one up myself.

I have the TH350 sitting in the car now, and I have a TH200R4 laying in the garage, made some noises in 1st gear, and reverse.

But I've heard that the TH200R4 is a weak trans overall? 🤔

 

New or rebuilt motor... you will have your foot in it more "playing"...been my experience.

Don't get hung up on HP numbers since it's nothing to you really and it's a street car.
Torque is what moves you and puts you back in the seat.
Cubic inches make torque in the lower RPM's...great for your plans.
Don't get hung up on high compression, as it will need better fuel...$$$

Now, whether you build yours or buy one built is up to you. Eagle use to make a decent 383 rotating assembly (kit) but you will still need machine work.
What heads, and intake do you have ? (kit below would need 72cc heads for about 9.5:1 compression)

CHEVROLET Eagle Specialty Products B15404E030 Eagle Street Performance Rotating Assemblies with Silv-O-Lite Claimer Pistons | Summit Racing

 

As for compression ... My build utilized 68cc chambered heads, 18cc dish pistons, pistons are at zero deck (a couple above deck by about .006), using an .051 head gasket, putting static CR at 9.23 and with the rather mild cam 7.56 dynamic CR.

 

If you’re not putting sticky tires and beating in it the 200 will be fine.

 

I think the 383 would suit me better. But if I find out the engine is numbers matching, I will consider building that.

 

Still waiting for the numbers....🙋‍♂️🙋‍♂️🙋‍♂️

 

And here's a picture of my car Can't wait for summer!

 

I did some research on the numbers myself. Correct me if I'm wrong. Full size, would that make it not out of a camaro, and therefor not numbers matching in my car?

And over to the engine, is this a good or bad engine? Could it still have 350 internals?

 

I did some research on the numbers myself. Correct me if I'm wrong. Full size, would that make it not out of a camaro, and therefor not numbers matching in my car?

And over to the engine, is this a good or bad engine? Could it still have 350 internals?
View attachment 301377

Correct. A full size is not a Camaro.

 

I don’t know if a previous post made it to you go online to Carl’s Chevrolet with a K brand new 350, 7200 bucks two years 50,000 mile warranty 357 guaranteed horsepower for 107 pounds of torque I just bought it put it in two months ago. It’s bad to the freaking bone. You can’t beat it. Don’t buy any of this other bullshit, this is the way to go spend the money do it

 

I don’t know if a previous post made it to you go online to Carl’s Chevrolet with a K brand new 350, 7200 bucks two years 50,000 mile warranty 357 guaranteed horsepower for 107 pounds of torque I just bought it put it in two months ago. It’s bad to the freaking bone. You can’t beat it. Don’t buy any of this other bullshit, this is the way to go spend the money do it

107 lb ft of torque ? hope that's a typo cause thats sad.
They ship overseas too?

 

 

Having done this conversion and also with Blueprint, you won’t be disappointed. It will be less expensive for the power, than trying to build that 350. Building the 350 can be rewarding also, can get to the same place and use what you have but I think given your location, access to parts and shipping, you’ll pay.

 

I had 700r4 for my 68 Camaro and the Transmission builder said the case was identical to the 200 just the input shaft was smaller so used the 700 and he required a valve body from a early 80s iroc or vett 700r because it was much thicker and could handle the drilling he would need to do to it but he built it to be all mechanical no electric for the 68 and could handle the 400ci small block we're to be using.

 

The 327 is a good motor to build but I suspect, especially in Norway, to rebuild it well and make power (will not have as much HP or TQ as the BPE 383) will cost more or certainly as much as the BPE.

Machine work for a .030 overbore, polish crank, new rods and pistons, new heads & cam and carb would likely be about a 350hp build. Then it is still a 2 piece RMS motor.

The BPE will be more plug and play and come with a warranty, have 1 piece RMS and a full hydraulic roller cam and make more HP and TQ

The current rear gears will be a dog even with a 3500 rpm stall TC. I would and did go to 3.08 with my BPE & TH350 combo. I do have a 2k RPM stall converter which you will minimally need regardless of 327 or BPE motor. Yeah lower rear gear with the TH350 will accelerate faster but when you are making the power of the 383 with its higher TQ, 3:08's will boil the rear tires and accelerate fast and still have decent Hwy RPM. I swapped from 3:73 to 3:08 gears because Hwy RPM's were just too high and I drive a lot of Hwy at 70 mph

 

Thinking of installing a 383 blueprint engine in my 68. It has a lazy/weak 350 in it now with 1406 edelbrock carb, edelbrock intake manifold and headers. I therefor have a few questions regarding the upgrade.

1. How much hp does a stock TH350 handle? And whats the best upgrade option?
2. How much hp does a stock open diff 8.2 rear end handle?

I know these two questions depends on the driving style, but I'm thinking of mainly just cruising, doing some light pulls now and then.

3: Could I use the same carb and intake manifold on a longblock 383, or should I go for something better?

And last but not least:
How much more fuel should I expect a 383 will use compared to my 350 when cruising/driving normally?

(In Norway were I'm located, the 98 octane fuel costs up to 10.75$ per gallon😬)

I had a Blueprint 383 strokes in my 67 Camaro. It sounded nice but lost the engine due to end for too advanced of timing causing 2 of the cylinders to burn up. They are refurbished World engines and not as reliable as I had expected. Went back to a stock SB 350 with SNIPER injection.

 

Any self-inflicted wound like having too much timing will kill any motor. IDK what year your BPE motor was but BPE has been using new cast blocks for SBC for some time now. They are cast in a foundry in Ohio and bear BPE casting in them.

Their youtube shop tour starts by explaining what they start with, new block.

IMHO if one has a Z or numbers matching SS or L30 motor than there is a position to take on keeping those drive trains original albeit they would need "rebuilding" so at that point they are no longer original but numbers matching which to some is important.

A Gen 1 SBC will always be hard pressed to perform better (more HP/TQ) than a 2nd gen SBC block using modern heads and cam let alone full hydraulic roller and 1 piece RMS

 

If the engine is numbers matching, fog the motor, pull it and store it. Get yourself a good BPE. You won't regret it. My experience is that you won't run the engine as hard in any given scenario. Gas mileage will not suffer.

 

3: Could I use the same carb and intake manifold on a longblock 383, or should I go for something better?

It depends. Which intake is paired with the 1406? Edelbrock says the 1406 is not a good match to the Performer RPM (in their FAQ). Otherwise, I'd ask Edelbrock about your specific pairing.

 

Thinking of installing a 383 blueprint engine in my 68. It has a lazy/weak 350 in it now with 1406 edelbrock carb, edelbrock intake manifold and headers. I therefor have a few questions regarding the upgrade.

3: Could I use the same carb and intake manifold on a longblock 383, or should I go for something better?

You can use your Performer Intake and 1406 carb on the 383 but I would and did get the Edelbrock Air Gap intake and used my 1406 carb. The Air Gap is good to 6k rpm vs the 5k rpm of the Performer

With the 383 you would want to get the 1406 carb jet kit as you would, like me, find you need to make some adjustments for the more powerful 383. I took baby steps following the grid instructions for "power mode" by first swapping the metering rod size to smaller but found I needed 1 jet size more so did that and put back in the stock metering rods. The carb kit comes with a variety of rods, springs and jets

I found my MPG to be about the same as my 327 using the same 1406 carb. 14-15 mpg on either motor

 

Chevrolet never offered the 327 in a 4 bolt main production car. 68/9 a limited run of industrial engines, very rare if that is what you have someone swapped it in.

Yes any 4 inch bore can be made into 302, 327, 350 based on internals. But why? I have had 302, 327 with 4.11 4.56, 4.88 gears. I would take a 383 or 406 on the street.

Why it seems "lazy" as you described it is the 2.73 gears and 2.52 1st gear TH350 & taller tires. Your 8.2 would need a new series 3 carrier to go numerically higher. The 8.2 series 2 is for 2.56 & 2.73 gears only, series 3 is 3.08 to 3.55. IF you have an 8.2 series 2 posi carrier congrats! Extremly rare. So much so in 67 all Chevy passenger cars ordered with 8.2 10 bolt 2.73 POSI GM automatically upgraded to 12 bolt rear ends, including 6 cylinder cars. Great deal!

The 2.73 ring gear x the 2.52 TH350 first gear only make for total gearing for first gear of 6.87:1. Add the likely 1.5 inch taller tires you have it knocks it down to 6:1 ish total gear in first. You will be much happier around 9:1 or 10:1 in first. The shorter stroke is hindering your low end torque. Those 2 things combined is why you aren't happy with its launch. A 327 or 302 can be built to make big power but need a lot more gearing, cam, compression and then it'll still take a higher launch rpm. I run a 2.73 behind a Doug Nash/Richmond 5 speed, no overdrive. First gear is 3.28 x 2.73 = 8.9:1 total first gear. I am considering going 3.08 for 10:1 first gear total gearing. Gears 1-4 match identically a 4.11 rearend close ratio Muncie car, with a 3.08 gear it matches a 4.56 rear close ratio Muncie car. 5th gear is 1:1 so 2.73 or 3.08 = highway. Your gearing can kill your joy or wake the car up. If I go 3.08 it will run like a 4.56 Muncie gears 1-4 but 2600 rpm in fifth gear @70mph, the muncie car has to turn 3956 rpm @ 70 mph.

Play around and sort out your gearing, then either rebuild your 327 as a 350, or buy a BPE 383. I would buy a 383 before building one unless you have done it before, requires careful checking of some clearances and selection of components, but you can do it. Personally I like 400 sbc, why give up the larger bore, unshroud the valve a little, thats just me. A 700R trans gives you a 3.06 1st gear I believe, but look for one 1987 or 88 and up when they had them sorted out and before things went electronic. The longer stroke 383 is easiest path to low end streetable broad torque band. Consider how you will use the car, 8.2 with upgraded 1541H axles, posi carrier can live on the street with no slicks or big sticky tires. If you do keep the 8.2 and go 3.08 gears opt for the 37/12 gear set vs the 40/13 (1st # is ring gear teeth, 2nd is pinion teeth). Both make a 3.08 but smaller pinion create less heat, longer life and better acelleration. Hidden gem is an 8.5 corporate 10 bolt add 30 spline axles & posi carrier, already has same size pinion diameter as a 12 bolt and 7/16" ring gear bolts, 12 bolt shares the 8.2 3/8" bolts. About half the cost of a 12 bolt.

Good luck, beautiful car, best year!

 

Chevrolet never offered the 327 in a 4 bolt main production car. 68/9 a limited run of industrial engines, very rare if that is what you have someone swapped it in.

Yes any 4 inch bore can be made into 302, 327, 350 based on internals. But why? I have had 302, 327 with 4.11 4.56, 4.88 gears. I would take a 383 or 406 on the street.

Why it seems "lazy" as you described it is the 2.73 gears and 2.52 1st gear TH350 & taller tires. Your 8.2 would need a new series 3 carrier to go numerically higher. The 8.2 series 2 is for 2.56 & 2.73 gears only, series 3 is 3.08 to 3.55. IF you have an 8.2 series 2 posi carrier congrats! Extremly rare. So much so in 67 all Chevy passenger cars ordered with 8.2 10 bolt 2.73 POSI GM automatically upgraded to 12 bolt rear ends, including 6 cylinder cars. Great deal!

The 2.73 ring gear x the 2.52 TH350 first gear only make for total gearing for first gear of 6.87:1. Add the likely 1.5 inch taller tires you have it knocks it down to 6:1 ish total gear in first. You will be much happier around 9:1 or 10:1 in first. The shorter stroke is hindering your low end torque. Those 2 things combined is why you aren't happy with its launch. A 327 or 302 can be built to make big power but need a lot more gearing, cam, compression and then it'll still take a higher launch rpm. I run a 2.73 behind a Doug Nash/Richmond 5 speed, no overdrive. First gear is 3.28 x 2.73 = 8.9:1 total first gear. I am considering going 3.08 for 10:1 first gear total gearing. Gears 1-4 match identically a 4.11 rearend close ratio Muncie car, with a 3.08 gear it matches a 4.56 rear close ratio Muncie car. 5th gear is 1:1 so 2.73 or 3.08 = highway. Your gearing can kill your joy or wake the car up. If I go 3.08 it will run like a 4.56 Muncie gears 1-4 but 2600 rpm in fifth gear @70mph, the muncie car has to turn 3956 rpm @ 70 mph.

Play around and sort out your gearing, then either rebuild your 327 as a 350, or buy a BPE 383. I would buy a 383 before building one unless you have done it before, requires careful checking of some clearances and selection of components, but you can do it. Personally I like 400 sbc, why give up the larger bore, unshroud the valve a little, thats just me. A 700R trans gives you a 3.06 1st gear I believe, but look for one 1987 or 88 and up when they had them sorted out and before things went electronic. The longer stroke 383 is easiest path to low end streetable broad torque band. Consider how you will use the car, 8.2 with upgraded 1541H axles, posi carrier can live on the street with no slicks or big sticky tires. If you do keep the 8.2 and go 3.08 gears opt for the 37/12 gear set vs the 40/13 (1st # is ring gear teeth, 2nd is pinion teeth). Both make a 3.08 but smaller pinion create less heat, longer life and better acelleration. Hidden gem is an 8.5 corporate 10 bolt add 30 spline axles & posi carrier, already has same size pinion diameter as a 12 bolt and 7/16" ring gear bolts, 12 bolt shares the 8.2 3/8" bolts. About half the cost of a 12 bolt.

Good luck, beautiful car, best year!

Thank you for a very informative answer. Regarding the 4 bolt, I only copied what I found on the decode site, but I would be very surprised if it actually had 4 bolt main caps.

Regarding the rear axle ratio, that's what I suspected all the time, it irritates me that I never got to the point of installing my tach last summer. I've always wondered what RPM's the engine is working at. But the 2.73 is really nice for cruising.

Since it now looks like it isn't a #-matching engine, I doubt that I will spend money on that. Think I'm going for a 383. But first I would like to change out the gearing in the rear. I have an open diff now, and I'm currently looking at a complete 3.36 Posi kit from Quick Performance. Anyone in here running this differential?

Thank you, I'm very happy with the car! The only one in my area. A lot of mustangs and old c3 corvettes, but no 1/2 gen camaros.

Had 2.73's a ways back...3.08's not really any better. (not worth the cost or time to swap)

3.55 would be my max for a street car.

Thanks for your reply, I was looking at 3.08 but I think I'll go for 3.36.


And another thing, I think I'm going to start with the gearing in the rear before doing anything with the engine. But would I see some improvements with a better cam on a 327, or is this wasted money? If not, which cam should I choose? Roller or flat tappet?

 

Had 2.73's a ways back...3.08's not really any better. (not worth the cost or time to swap)

3.55 would be my max for a street car.