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post #1 of 33 (permalink) Old Sep 28th, 04, 06:25 PM Thread Starter
 
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Okay guys let me have it.

I am finishing up the conceptual build of my new engine and would love some input from you guys to see how I can do it better or what problems I may not be seeing. I have decided to build a 383 for my 67 RS/SS vert, deciding not to rebuild the 67 350 SS engine I have and originally planned to do. (no, it is not numbers matching ) It will be a 98% street motor with a few 1/4 mile runs,when I can make it to a track. (I do not plan on spinning it higher than 5500-6000rpm, and I want good low end torque.)

That said, I know I will use a four bolt main block with flat top pistons (Keith Black hyper, SLP, etc.?), (with valve reliefs) forged crank (Eagle), 64cc aluminum 23 degree heads, Trickflow's most likely, but still considering AFR's). toping it will be a dual plane intake (RPM Air Gap) and a 780 to 850 cfm carb (Demon or Holley). This dumps into full length Hedmans into 2.25 inch dual exhaust with an H pipe. I am up in the air about the Cam but would like something similar to the ZZ383 Cam (222* int., 230 ex. @ .050", 509 and 528 lift).

Anyway I need opinions on piston, carb and cam selection, best rockers to use with this setup, as well as what HP and torque I can expect this setup to make. I have thought about buying a complete rotating assembly also.

Oh yeah this is running through an Muncie M20 to a 3.08 posi 12 bolt. After I ger the engine built, installed and running, and make some more money, I will put a TKO 600 in it and change the rear gears to 3.55's or 3.73's.

Thanks for the help/advice in advance.

Victor
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post #2 of 33 (permalink) Old Sep 29th, 04, 04:13 AM
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Since you said the engine is mostly for street use, there is no real need to go with the flat top pistons in a 383 -- you really want a D dish IMO unless you go with a head that has a larger combustion chamber.

This is the deal . . . 64cc heads and a flat top piston will make 11:1 or more in a 383 -- way too much for pump gas unless you run a pretty big cam. If you get heads with 72cc combustion chambers the compression drops to 10:1 with flat tops -- just about perfect for a mild street 383. If you get 64cc heads you can use a -12 to -18cc D dish piston that will make about 9.5:1 - 10:1 compression, again just about perfect for a mild 383.

You do not need a forged crank. I run an Eagle cast crank to 6500 RPM in my 383 and its going strong after 4 years. I would look into the Scat 9000 series and their matching I beam rods to go with the crank. Machine work from Eagle has been suspect lately so be very careful, Scat is better.

As for heads, I run the TFS 23* ones that you mention and am very happy with them. They should work great for your mild 383 and are available in either 64cc or 72cc versions (72cc with a flat top piston would be my first choice).

As for cam, if you want to go hydraulic roller I've heard great things about the GM Hot cam kit. It is sized correctly for your compression and gear ratio although more gear would really help a lot down the road. There are a lot of cam choices out there -- its hard to nail down a cam though until you know which heads and compression ratio you are using for sure.

ps. There are a lot more choices in flat top pistons out there than -12cc D dish pistons. KBs are OK and they make a -12cc piston, but I broke a set in my 383 a couple years ago. Have been real happy with my SRP forged flat top slugs . . .

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post #3 of 33 (permalink) Old Sep 29th, 04, 05:28 AM Thread Starter
 
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Eric,

Thanks for the reply.

I wasnt sure of piston height in a 383 and how it would affect the compression ratio. (this is my first attempt at a 383, I have always done 350's before.) I do want to run around 10 to 1 compression or just a hair under that. I think I will use the 72 cc trickflow heads so I can stay with the flat tops. (I know this isn't necessarily correct, but I have always sort of associated dished pistons with lower performance, flat tops and domes with higher performance)

I know I dont need a forged crank, but for the money I will put in to the total engine, I would like that extra strength. When it comes time to buy everything, going with a cast crank to save money will be something I consider. I have heard more good than bad and bad things about both Eagle and Scat, but have only had personal experience with the Eagle. If you are running an Eagle crank and are recommending a Scat, I guess I need to re-evaluate the crank choice.

As for the cam, I am not sure what to look for for my engine application. All engine work I have done is on the older two piece rear main seals, with old camel hump style heads. (non vortec or centerbolt heads). I really like the broad torque curve on the ZZ383 cam, are cam's interchangable between old style vs. vortec style heads and 1 and 2 piece rear main seal blocks? (Are GM fastburn heads center bolt?)

Is the carb size big enough?

I have always thought dual planes were better for low torque. Are there any single planes that work well for low end torque that I should consider?

Thanks again for your help.

Victor
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post #4 of 33 (permalink) Old Sep 29th, 04, 05:34 AM Thread Starter
 
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Eric,

I forgot to ask which springs I should get in the Trickflows, and is getting an assembled head going to affect my cam choice?

Thanks again.

Victor
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post #5 of 33 (permalink) Old Sep 29th, 04, 06:17 AM
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I would just reiterate what Eric said...be REAL carefull on the compression. With a .041 compressd gasket, 5cc valve relief flat tops and 72cc heads I get 10.16. With aluminum heads and an aggressive cam that is no problem for pump gas. If you are going to go with a fairly short duration, high torque cam I would err on the side of caution and be sure to keep it under 10:1. You can do that by simply putting the piston down in the hole a little, or get a dished piston.

69 Camaro, 3650lbs., 400ci, TH400, Coan 10" converter, 3.50 gear
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post #6 of 33 (permalink) Old Sep 29th, 04, 08:41 AM
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To clarify, I bought my Eagle crank 4 years ago and it is a good piece -- no problems, good machine work. Recently, I have heard some complaints about machine work coming from Eagle. No complaints about Scat.

As for the valve springs, it totally depends on what cam you get. I wish head manufacturers would sell finished heads with the valves only. Then you could get the cam kit with the right retainers and springs for your cam instead of generic "roller" springs or generic "solid FT springs."

To answer your question . . . you need to figure out what cam first, then pick the springs. Hopefully you can order the TFS heads with the ones you need.

E85 racer and E85 carb builder

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68 Camaro, E85 powered 427" small block. 9.96 @ 133 MPH, 1.319 sixty foot on motor. 5.92 eighth @ 116 with a 1.42 sixty breaking beams with back tire on the bottle
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post #7 of 33 (permalink) Old Sep 29th, 04, 01:23 PM
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To answer a couple of questions and possibly clear up a point:

Are you aware that the ZZ383 cam as well as the GMPP hot cam are both hydraulic rollers? (A great choice, BTW, if you plan on running 5500-6000). I ask because both cams listed are designed for use in factory roller blocks. They can be used in earlier blocks but require a bit different install and conversion type hydro roller lifters. The cam bolt circle is smaller and requires a roller block cam gear.

The ZZ383 and the hot cam are very similar. The ZZ383 has a slight bit more duration, and the hot cam has a bit more lift. also be aware that the ZZ383 cam specs are based on 1.5 rockers, and the hot cam is based on 1.6.

As for spring specs for the hot cam, here is the cam card that spells it out quite nicely:



Up to about 5500 the hot cam pulls like crazy and has only a slight lope at 700 rpm idle and gobs of vacuum for brakes.. There are certainly bigger hydro rollers out ther that will move your power band up in the rpm range. The comp xr282hr comes to mind.

Since I already had the Fasburn heads, I went with Wiseco -20cc D-Dish pistons. With a reasonably tight quench, my CR is at 9.6 with 62 cc heads. If I were starting from scratch, I'd go with flat tops and bigger chambers (although if I ever decide to add a blower-YEAH RIGHT- I'd only need to change heads.)

PS The GM Fastburn heads are drilled and tapped for both centerbolt and peripheral bolt valve covers.

PPS I had mucho trouble with my Eagle crank, but it was a forged one that I bought on E-bay as a factory blem. Lesson learned!


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post #8 of 33 (permalink) Old Sep 29th, 04, 02:13 PM Thread Starter
 
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Eric & Greg thanks for your help.

I just read my second post on this thread, I wasn't very clear, and honestly I sound like an idiot. To clarify,are there any design changes between one and two piece rear seal blocks, and old style heads and vortec or center bolt VALVE cover heads that affect cam selection. I know this affects manifold selection, but I am not sure about cam's. Also searching old posts, small base circle cams are discussed for use in 383's. Can these be used regardless of block or head selection?

Thanks again for your help. Remember "there are no stupid questions, just stupid people"

Victor
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post #9 of 33 (permalink) Old Sep 29th, 04, 02:34 PM Thread Starter
 
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Thanks Al,

That cleared up alot of questions. I started the above post before dinner and just finished it. That is exactly what I wanted to know about the cam application. I really like a hydraulic roller since I dont plan on spinning it that high but didn't know if It would work in an old style block. What are the cons of going to a hydraulic roller on an old style block. If there are too many drawbacks or the hassle or cost is too high, I may as well buy a shortblock and be done with it. (But where's the fun in that? ) A while back I had thought about building a stroker that looked pretty much like a stocker, but with an aluminum intake manifold, but now it would be awful hard to diguise a set of performance aluminum heads.

Thanks again,

Victor
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post #10 of 33 (permalink) Old Sep 29th, 04, 05:43 PM
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For the rpms your looking at, there really is no need for a forged crank. I am using a scat cast steel crank (stronger than cast iron, but not quite as strong as a forged piece), and scat 7/16" capscrew rods, and a set of wiseco 2 vlave relief forged flat tops. I am also using a set of 72cc chambered pro-topline iron heads, and with a 0 deckheight and .038" thick head gasket, I am right at 10.3-1 compression. With a relatively small cam this would be a problem, but with my [email protected] solid cam, I get 185psi cranking compression (which would probably run on 87 octane with these heads). A high rise dual plane intake like a performer rpm or a 300-36 holley makes a great street intake for these engines, and helps create more vacuum and stronger low end response than a single plane. A 750 cfm carb is all you need. I didn't know trick flows come in a 72cc chamber, but if they do, they would be a good choice with a flat top piston. A 18cc dished pistoned 383 with a 0 deck and 64cc heads will be right about 9.7-1. Modern d-shaped dished pistons are worlds better than the old style round dished factory style pistons, and many engine builders claim that a smaller chamber with a d-dished piston is THE way to go for a street engine.
My only other comment is about your exhaust pipe selection. 2 1/4" is really too small...go 2 1/2" if you can.

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post #11 of 33 (permalink) Old Sep 30th, 04, 07:07 AM Thread Starter
 
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Thanks for the reply Travis.

I know there is nothing wrong with todays dished pistons and If I cant get my CR to ten or just below it I will go with them. But I still associate the dished pistons with the end of the musclecar era when Chevy went from flat tops and domes to dished pistons around 72 or 73 (no I am not that old.)

I know flat top pistons come with different sized valve reliefs. The pistons I was looking at were flat tops with 7cc valve reliefs. With a 72 cc combustion chamber on the head, what is my compression going to be? How much would it change with a 74cc head?

How much more of a cam do you guys think I can get away with before I lose streetability. I dont mind the RPM band kicking in a little higher but keep in mind right now I have 3.08 gear with a muncie M20.

What I don't want now is an engine like I had back in my 68 SS in the early 80's. (teenage gearhead days) 350cu in 030 over, 11cc domes about (12:1 CR), Weind single plane 800-850 holley DP etc. I cant remember the cam specs but the power band was around 2700-6500+ RPM. It had 3.55 rear gears with a M22. The launch in my vert is about the same 7.76 vs 7.81 then but I am running shorter tires now 26.1" now, 27.5" then.

My point is I just remember what a pain it was driving in stop and go traffic, but man would that thing scream from 20mph on up. I think I could get away with something a little closer to that (the cam,not the CR),now if I had 3.73 or 4.11's with the m20, but I dont want to be turning 3000+ on the highway either. I still love the kind of performance of that 68 (very fond memories), but now I just want something with better street manners, for when I am stuck in beach traffic during the summer, and cant get the thing out of 1st gear. Later I'll get a TKO, change the rear gears, and then I'll think about a cam upgrade.

Al, what is involved in a hydraulic roller retro fit and are there any durability issues with the retro fit?

Eric, Who is an online vendor for the SRP pistons so I can do some research on them?


Again, thanks for your time and help.

Victor


P.S. I just thought of something on the cam I know you can use more lift and duration on a 350 as compared to a 327, so I guess that also holds true that you could get away using a cam with more lift and duration on a 383 as compared to a 350. Is that correct?
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post #12 of 33 (permalink) Old Sep 30th, 04, 08:44 AM
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Eric
 
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Try www.dirttrackthunder.com

I agree with Travis about using a small D dish with a small chamber instead of flat top with a bigger chamber. There has been some interesting discussion about the D dish chamber shape making a scosh more power . . .

The only problem I found with that is that there seems to be a real limited quntity of -12cc dish pistons for a 383. KB makes a hyperutectice one, but I am not aware of anyone else that makes a good forged piston. There are plenty of -18 to -21cc slugs out there but that drops the compression a bit too much for my tastes (down to 9.5-9.7:1).

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68 Camaro, E85 powered 427" small block. 9.96 @ 133 MPH, 1.319 sixty foot on motor. 5.92 eighth @ 116 with a 1.42 sixty breaking beams with back tire on the bottle
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post #13 of 33 (permalink) Old Sep 30th, 04, 08:47 AM
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Al
 
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Quote:
Originally posted by Obxhokie:
Thanks for the reply Travis.


Al, what is involved in a hydraulic roller retro fit and are there any durability issues with the retro fit?


The two main things to deal with in a roller cam are:

1. There needs to be a provision to keep the cam from moving forward in the block. On retrofits, this is usually called a "cam button", which is a small bearing that is attached to the inside of the timing cover.

2. The lifters can not spin in their bores like a FT lifter. The cure for this is a bar that connects the lifters in pairs.

The Chev factory rollers have a slightly different method for achieving each of these - rather ingenious but in my opinion neither more nor less effective.

Ther are other issues with hydro rollers - valve spring needs come to mind, but you should buy springs that are compatible with the cam no matter what type you use.

Hydraulic rollers (AFAIK) have a very good rep for durability. The biggest downside for a performance application is that the lifters are heavy and they tend to float the valves in the 6-6500 range.

If you want to know specifically how to install a GM hyd roller cam in an early block feel free to ask. It's not that big a deal, but personally, I'd look to a retrofit aftermarket cam as there are many more choices.


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post #14 of 33 (permalink) Old Oct 1st, 04, 06:08 AM Thread Starter
 
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Thanks for the info Al,

I am not set on a GM cam, in fact I would prefer it to be a comp, crane or isky cam, but something similar with maybe just slightly more duration than the hot cam, and lift numbers like the ZZ383 cam (using 1.5 rockers). Do the 1.6 rockers just provide more lift or are there other benefits to using them? (like better valve control, helping to reduce valve float etc.)

Also, the more I have researched Compression ratio with my cam choice, I am second guessing myself. Should I be looking at a CR in the 9.5 to 9.8 range? I see that you are running 9.6:1. Do you have to use premium fuel with that hot cam? Have you changeed your cam yet? If so how did it affect the street manners? I know you are running an auto, but the more info I can get, the more comfortable I will feel about the cam choice. (The biggest issue that I am not quite comfortable with yet)


Thanks again,


Victor
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post #15 of 33 (permalink) Old Oct 1st, 04, 08:14 AM
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Al
 
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The reason I went with 9.6:1 was really a result of the fact that I already had my 62cc Fastburn heads. Flat tops were out of the question (11:1+), and as Eric said, there aren't many (if any) off the shelf -12cc d-dish forged pistons out there. So I went with the -20 cc Wisecos, as they give a respectable 9.6:1. I have never run anything other than premium so I can't comment on that. I will say, though, that I don't see pump gas octane ratings ever going higher, but I can envision them going lower, so I feel safe with my CR.

The hot cam was designed to provide its advertised specs with 1.6 rockers (not sure why) - and yes, they simply provide more valve lift. They may also add just a bit more duration, but probably not enough to make much difference.

I have not changed my cam yet, and am still really up in the air as whether I will or not. I keep telling myself I want more power, but the reality is is that I am VERY pleased with the way the motor runs now. Since I don't and won't drag race this car on any kind of regular basis, having the power band down in an area where I actually drive the car makes most sense to me. A bigger cam would simply move the torque peak to a higher point in the RPM range, and naturally more horsepower would follow. But driveability would suffer, and since this car IS a driver, I'm not sure I want to take that chance.

So my advice, cam-wise, would be to first decide on what you want to do with the car - race it or drive it, and cam it accordingly. It sounds like a driver is your main use, so go easy on the cam. Let the cubes do the hard work and you'll be happier.

[ 10-01-2004, 11:37 AM: Message edited by: BPOS ]


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