Team Camaro Tech banner
Cancel
Create thread New Garage Forums

383 Build up for my 69 Camaro

Jump to Latest
1 - 20 of 46 Posts
M

matt4723

· Registered
Joined
·
17 Posts
Discussion starter · #1 ·
350 4 bolt main
.030 Over
Speed Pro Forged Pistons P/N L-2491f30
Sportsman 2 heads 64cc
Hyd Roller Cam That comp cams helped me out with..P/N 12-422-8 Duration @.050 In 218 Ex 224
5.7 Reconditioned Rods From PAW
ARP Bolts throughout
Torqer 2 Intake....Should of when"t with a nice duel plane like the performer but to late now..I will just "Borrow" my friends rpm intake to see if it would be better.
Perform 1.5 Roller Rockers Jegs 077-866907
Roller lifters jegs 027-011515
MSD Pro Billet HEI
High Flo 160 Thermostat
Dynomax Ceramacoat Headers


Just wondering if every thing looks good or any ideas...what do u think compression might be...or cause any problems....Would this engine last over time....I may drag it one or two times...just to see what it would do...but manly just a street car.....Would it run good on pump gas or should i try cam2 fuel..that a friend of mine recommened Thanx Matt
 
#2 ·
Your compression with a zero decked block and .041 head gasket would be 10.4:1. Those pistons are flat tops with -3.4cc valve reliefs according to the Speed Pro catalog.

I think the cam is on the small side for pump premium with your compression ratio and iron heads. I get 8.60:1 DCR using 270/276* advertised, 110* LSA, 106* ICL.
 
#3 ·
and if I can add, if you haven't bought the heads yet, check out the Dart Iron Eagles and Pro Topline heads before you buy the Sportsman II's...and Eric is correct, cam is kinda small for a bigger displacement 383.
 
Save
Reply Quote Like Like
#4 ·
If those pistons are in fact flat tops as Eric stated, your compression ratio with 64cc chambers and a .041 quench will be more like 11.3:1 in a 383. I'm thinking Eric might have figured your compression for a 350?

[ 01-05-2004, 08:49 AM: Message edited by: BPOS ]
 
#5 ·
Ah, yes, good catch BPOS.
Image
I went with the first line in the post that says, "350 4 bolt block" and calculated for a 355 cid engine.

Compression ratio is 11.2:1 and DCR is actually 9.25:1 with the small HR cam.

I would hold off on both the cam and the heads. You can use those flat top pistons if you already have them if you get 72cc chamber heads. that would drop your static CR down to 10.25:1. Then go a size or two bigger on the cam and you will be OK with pump gas. You could go with a dished piston if you are already saddled with the heads.

I agree that the ProTopline 72cc heads with 180 or 200cc runners (depending on cam selection) would be the best bet. With the aluminum version you could stay smallish with the cam if you want and be fine with pump gas.

PS. Comp says the RPM range is 1600-5400 for that cam in their catalog. "largest for stock converter"
 
Discussion starter · #7 ·
One Problem guys...I already have all parts bought...And it is running in the camaro already...lol...Have 2000 stall converter..and wanting to run like 3.43 gears has 4.11s now...wow talk about gas guzzler..lol..th400 trans..It seems like it runs good...she will turn a corner sideways like u wouldnt believe...The only prob i am having is the timing...right now i have it set between 8 and 10 initial cause if i go any more it pings..and it seems like it was pretty close...And the other prob is the carb...Eldebrock 750 manual...hell of a time getting it tuned in...Any suggestions?
 
#9 ·
:eek: Uh ya...That's MUCHO HIGH for that cam and pump gas.

My guess is the only reason that you don't hear detonation all the time is the 4.11's.
I'll bet as soon as you install 3.42's the rattle will drive you nuts.

I think I would leave the vacuum advance unhooked.

It ain't going to be a high mileage motor cause it will kill it's self from the detonation.
 
#11 ·
what do you think guys?
dished pistons or a really long cam(if you were to pick just one)?
 
Save
Reply Quote Like Like
#12 ·
I think high octane fuel is his only choice at this point. Swapping the cam might help for part throttle cruising nut, when he jumps on it it will still rattle. If he continues to run pump gas and ping/detonate it he will have a chance to change the pistons real soon.

Keep your timing VERY conservative and keep the gears for now. I agree switching to 3.42's will only make things worse. The easiest fix is to swap heads (not the cheapest, but the easiest).

Seriously this engine is not going to live long on pump gas so you might want to cut your losses and do something about it now/real soon.
 
#15 ·
You cannot always HEAR detonation. Just because you don't hear pinging doesn't mean its not happening.

As the others said you WILL destroy your motor driving it on pump gas in short order. Either lower your compression ratio, or add a lot more cam, or run race gas; if you don't you WILL break your engine - maybe sooner, maybe later.

If you are unwilling to change anything now because its already built why did you bother asking us?
Image
 
Discussion starter · #16 ·
If you are unwilling to change anything now because its already built why did you bother asking us?....Because it was in the way back of my mind that the compression was to high...u guys just conformed it for me....Thanx
 
Discussion starter · #18 ·
That is good to here....and i may think about doing that...but i may keep runing it with cam2 and mix it to about 96 octain...that should keep her fed for a while...But if not...What would be a good small block to build with out busting the pocket...I am looking for plenty of passing power..but yet would run good @ cruising speed..... and be "ok" on mpg..For the camaro.
 
#19 ·
The small block in your car has everything you want, just slightly high on the compression. Instead of spending the money to build another engine, why not buy a set of 72cc heads? That will be cheaper, easier, faster than building a new engine.

Putting a band aid on on a gun shot wound is not going to heal it, you can either go in and fix it now or wait for it to get infected (hammered bearing, pistons, etc...) and have to have major sugery or take a chance of ruining the whole thing.

Going down a hill is not the problem, try going up the hill and putting a load on the engine, that's when you will have more detonation. Also the weather is cooler right now, wait until it heats up, you might have to back the timing off even more. The extra compression is going to waste already and the more you back off the timing the less power you will make. You already took away the added power the compression makes with the way the timing its right now (IMO).

It's your car and your wallet, if it is truly a street car that race gas will get expensive and if you don't run race gas, repairing/replacing the engine will be expensive. I don't think anyone here would try to steer you wrong.

What cam was in that 350 with 11.5:1 compression? Was everything cc'd or is 11.5 a guess? I would guess you either had a LOT of cam or the compression was not quite as high as thought. Also if you had a very high stall that would of helped.
 
Discussion starter · #20 ·
"What cam was in that 350 with 11.5:1 compression? Was everything cc'd or is 11.5 a guess? I would guess you either had a LOT of cam or the compression was not quite as high as thought"Here is what i got from Eric68
-------------------------------------------------
Ah, yes, good catch BPOS. I went with the first line in the post that says, "350 4 bolt block" and calculated for a 355 cid engine.

Compression ratio is 11.2:1 and DCR is actually 9.25:1 with the small HR cam.
 
1 - 20 of 46 Posts
About this Discussion
45 Replies
11 Participants
Last post:
Eric68
Team Camaro Tech
posts
2.4M
members
90K
Since
1998
A forum community dedicated to 1st generation Chevy Camaros owners and enthusiasts. Come join the discussion about performance, builds, restoration, modifications, classifieds, troubleshooting, reviews, and more!
Full Forum Listing
Explore Our Forums
Bench Racing Engine Body Shop Performance Brakes, Suspension & Steering