200cc too big for mild 350? pics - Team Camaro Tech
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post #1 of 14 (permalink) Old Jan 19th, 17, 12:40 AM Thread Starter
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Luigi
 
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200cc too big for mild 350? pics

Hey I scored big time. My uncle has Carpal Tunnel Syndrome and was forced to retire from GE. He has given up on his 70 Nova project so he gave me his engine..for free yes!! for free!!
I helped him put it together over the years but it sits on the stand and never turned over. Please don't kill me with the "why did he?" questions but I believe my uncle was triyng to copy or make better one of his work buddies Corvette engine so he may have been ill advised.

Here is what it is:

-2 bolt SBC 350 short block with all new stuff like Pistons, crank, bearings etc
-Summit 1103 cam: 288 int./298 exh. 0.444 int./0.466 exh. 112 Lobe Sep , he added 1.6 roller rockers so now it is at .473 and .496
-Polished Vortec dual pane intake with a nice early 80's Corvette Q-jet, double roller cam gear and Ceramic headers
-Nova has a 200-R4 tranny w/shift kit, stock stall with 3.73 Posi rear
-Heads: Skip White's NKB 272-200 that are 2.02/1.60 valves .550 max lift and 200cc intake runners

So here is the question Are these heads too big?
When he bought the heads I told him they might be too much intake volume and that he might need need a bigger cam. He said his buddy told him he'll have more power as he moves up on RPMs with the smaller cam and he should be fine. These GE Tool & Dye makers have a reason for everything so you never know. I think this guy set him up wrong so when they race his corvette leaves him in the dust

So do I run it or sell the heads?
My uncle's Nova has a cammed 305 I put in for him and drives fine so he is giving up on the 350.
I'm dropping this engine in my Convertible so I would need to invest in a new tranny and rear end. Pics have the wrong date(older digi camera)
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Last edited by 68barnfind; Jan 19th, 17 at 12:50 AM. Reason: adding pics
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post #2 of 14 (permalink) Old Jan 19th, 17, 03:45 AM
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Re: 200cc too big for mild 350? pics

I would run it just to show your Uncle the fruits of his labor....Whats the compression ?

Compression and rpm, the heads will work, but I'm leaning on more cam (depending).

68 Camaro~LSx ~all motor
1.54 60'--6.95 @ 98.45 660'--10.96 @ 121.53
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post #3 of 14 (permalink) Old Jan 19th, 17, 06:11 AM Thread Starter
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Re: 200cc too big for mild 350? pics

These heads ahave 64cc chambers. He never told me what headgasket he used or if he took record of piston clearance. I'm gonna have to call him later today. He did tell me his goal was to be around 10:1 or better.
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post #4 of 14 (permalink) Old Jan 19th, 17, 06:18 AM
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Re: 200cc too big for mild 350? pics

A head with 200 cc intake ports will work fine on a 355. It is designed for higher RPM than the street so you are going to be down on power at lower RPM until you can get the RPM up (you should be able to feel the heads start to pull if you wrap up first or second gear). The factory Fulie head had 170 cc intake runners for comparison. Cylinder filling is all about port velocity; bigger head is like a deep broad river it flows a lot but the current is slow, where a smaller river bed won't handle as much water but the current is faster. That is the difference between flow numbers and port velocity. You try and match your volume cfm with port velocity to get better cylinder filling to your intended driving style.

Your cam choice and rear gear will greatly affect your enjoyment with these heads.

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post #5 of 14 (permalink) Old Jan 19th, 17, 10:50 AM Thread Starter
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Re: 200cc too big for mild 350? pics

Thanks Doug and Dave, I'm planning on dropping it in my Vert but I was hoping if I mirror his rear gears and tranny I can least chirp the tires on take off. That's what he does this now with his Nova.
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post #6 of 14 (permalink) Old Jan 19th, 17, 01:27 PM Thread Starter
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Re: 200cc too big for mild 350? pics

Well I just got off the phone with my Uncle. No luck on Head Gasket part number but he said he used FelPro MLS type Racing gasket for higher compression. I started to look around for a 200-R4 and might as well just get upgrade my rear to 3.73 posi. I guess a higher stall converter will be needed too. Doesn't look like I will find a 12 bolt posi differential here in Connecticut junk

Should I get a better cam? Hydraulic roller possibly?
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post #7 of 14 (permalink) Old Jan 19th, 17, 08:54 PM
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Re: 200cc too big for mild 350? pics

Normally, I'd say those heads are too big for a street SBC, but if you keep that cam, it should work. However, I wouldn't expect it to make any usable power under 2500 rpms. To take advantage of that engine, you will need a minimum of 3.73 gears. If you run an automatic, you will need a higher than stock stall speed.
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post #8 of 14 (permalink) Old Jan 19th, 17, 10:09 PM Thread Starter
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Re: 200cc too big for mild 350? pics

Thanks Bill, If I have to keep giving it more gas just to move around town then I'm gonna have to get other heads. Knowing they will work is encouraging but it is what I suspected. I was hoping for some low end torque that I can feel. Giving it some pedal when leaving a stoplight and then even more to feel some real power is something I will not be happy with. I would be wasting fuel just to get some satisfaction. Going to swap these out now while it's on the stand.

I'm just started looking at these Summit heads that are cast iron (which I feel more confident in). They are Vortec style with 175cc runners, 67cc chambers and handle up to .520 lift. I got 2 girls in college and a 3 yr old still in diapers so I kind of have a tight budget Going to sell these heads and recoup a little back

I am hoping for at least 350 horse power, wish me luck
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post #9 of 14 (permalink) Old Jan 20th, 17, 06:13 AM
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Re: 200cc too big for mild 350? pics

You are on the right track. Your uncle built that engine for one purpose and you want it to fill a different purpose. Unless you live in a an area where you can wind it out, re-thnking that combo is the way to go.

If you want cast iron heads, the GMPP Bowtie Vortec heads are the way to go.
Small Port Vortec Bowtie Head Assembly : GM Parts Direct: Your direct source for Genuine GM Parts
GM's best cast iron head ever. Small port is 180-185 cc intake. Stab a cam that matches the flow portfolio and be happy. Takes all the bad things about the original Vortec and corrects them.
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post #10 of 14 (permalink) Old Jan 20th, 17, 08:40 PM
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Re: 200cc too big for mild 350? pics

I like those Summit vortec heads a lot. 20-40 hp over stock heads. A good value for the money. You could probably drop that cam down a notch or two and still reach your 350 hp goal.
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post #11 of 14 (permalink) Old Jan 21st, 17, 02:22 AM Thread Starter
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Re: 200cc too big for mild 350? pics

Thanks Chet for the link. Those heads are what I would buy if I had the extra funds, I still have to budget for the tranny and rear gears so looks like the Summits would be the huckleberry. I'm looking at a 200-4R tomorrow off a 86 Monte Carlo SS. Has around 80k miles and the guy wants $400. I might get it for $300 if I do a brake job on his work van.

Hey Thanks Bill, you really think this combo can reach my goal? Or would u suggest getting back to the 1.5 rockers instead of the 1.6 that are there now? The cam is kinda small... numbers are: lift is at 473/496 with the 1.6 rockers 214 duration @50 and 288 advertised, backing down to the 1.5 rockers would set it at .444/.466
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post #12 of 14 (permalink) Old Jan 21st, 17, 07:49 AM
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Re: 200cc too big for mild 350? pics

Quote:
Originally Posted by 68barnfind View Post
Thanks Chet for the link. Those heads are what I would buy if I had the extra funds, I still have to budget for the tranny and rear gears so looks like the Summits would be the huckleberry. I'm looking at a 200-4R tomorrow off a 86 Monte Carlo SS. Has around 80k miles and the guy wants $400. I might get it for $300 if I do a brake job on his work van.

Hey Thanks Bill, you really think this combo can reach my goal? Or would u suggest getting back to the 1.5 rockers instead of the 1.6 that are there now? The cam is kinda small... numbers are: lift is at 473/496 with the 1.6 rockers 214 duration @50 and 288 advertised, backing down to the 1.5 rockers would set it at .444/.466
Only down side to a higher lift rocker is the added stress on the rocker arm stud and the rocker arm (which will work harden at an accelerated rate if it is made of aluminum). That is about it. Other wise it is a winning idea. To counter act the metal fatigue I use chrome-moly rockers instead of aluminum, and a 7/16th inch ARP screw in rocker stud instead of the smaller stock 3/8th inch size.

If you already have the rockers I would use them (if aluminum just check them for cracks occasionally) as maintenance is part of the joy of owning a non-stock motor.

Big Dave
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post #13 of 14 (permalink) Old Jan 22nd, 17, 12:30 AM Thread Starter
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Re: 200cc too big for mild 350? pics

Thanks Dave, good to l know I'll be alright. The rockers look to be harden steel rollers. I offered 350 for the 200-4r Tranny , guys says he has it sold for $400......so the hunt continues.
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post #14 of 14 (permalink) Old Jan 22nd, 17, 06:28 PM
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Re: 200cc too big for mild 350? pics

The trans in the 86 Monte SS's is a good one to get. Better than a Monte LS.
A 350 with vortec heads, a 280/480 cam, 1.5 rockers, HEI, dual plane intake, 4 barrel, and headers should reach your 350 hp goal.
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