91CamaroRS305

iTrader: (2)

ok, i am building my new engine, i am looking for a non emissions car, i am going to change every thing, cam, pistons, throttle body, intake runners, and other stuff. i am looking to go with some speed pro .125" dome pistons on 64cc heads, says i will get 10.8:1 compression. but i was also looking at a bigger dome(.250") to get 12.7,
i am looking to put in a Lunati cam (adv duration 300; lift 515"; rpm ramnge 2500-6500) hydraulic cam set up,
i am getting slp runners,
i have after market injectors,
adjustable fuel presssure regulator,
th350 reverese manual valve body(or a 700 if i can find a built one) on a 2800-3200 stall,
and depending on what i can get either a 58mm throttle bodiy, or if anyone feels i will get the Accel 1000 CFM tb.
i also want to know if i should worry about the bottom end, i just got a bearing job about 3500 miles ago, its a bare block but shoudl i get higher speed bearing and a new crank or will the crank hold?
i will eventually change the suspension(control arms, panhard rod, shocks, torque arms, frame ties, etc)
i am looking to use a 150-250 shot of happy juice(maybe)
now is 12.7 compression too much for a TPI setup?
i am hoping for a base of 400 HP at the rear wheels w/o the nitrous

i am just seeing what you all think and if i should perhaps do soemthing different, but basically do i need to worry about compression or no? thanks a mil, when ever i get it done i will post some pics

91GTABird

First of all is this gonna be a daily driver or a weekend warrior? If its gonna be a daily then i wouldnt go with a 12.7 cr. 10.8 would be a good cr to go with. If you are going to go with the 12.7 then you might want to get a good aluminum head (ie. AFR). You going to have a fun time trying to run a 300* duration without some "good" prom work. The slp runners arent going to be real compatible with you setup unless you get or port a lower intake (ie. Edelbrock, Accel) and port your plenum. Unless you just wanted to go with a HSR, Mini Ram, or Super Ram. What # injectors do you have? The bearings and crank should be fine but i wouldnt chance the bearings with the 12.7 cr. If you are wanting to get 400hp then your really going to wanna get some SFC's. As for the "gas" i wouldnt think about spraying it with a 12.7 cr and you might not want to spray a 250 shot with 10.8 cr.
58mm Tb will be plenty. I didnt know you could buy the accel 1000cfm TB seperatley, thought it only came with the the Street Ram. Theres still alot of other stuff i have left out that others will make up for.

3.8TransAM

My cranking compression is somewhere in the 11 to one range !!!!!! Came out a lil higher than it was supposed to On a compression test i get 196 to 203#'s on all 8 cyl...

I wouldnt try pushing much higher on the street as it goes up so does the abuse the ords suffer as was mentioned earlier :-) Im currently in the process of supercharging it with a eaton roots blower and converting to a 749 ecm :-) Figure with some intercooling and 6-8 psi it will live :-) for how long i dunno but dont have lots of $$$$$$$$$$ in ti so if it dies then i know it was a lil too much :-)

Above all start small and work your way up whether boosting it or using nitrous, always start on the small side adn work upwards then u shouldnt get yourself into trouble as long as u keep notes :-)

And all the above on my car with myself doing the prom tuning(which u should consider with the kind if stuff u r doing)

Later
Jeremy

91CamaroRS305

iTrader: (2)

if i were to go carbed might i avoid all the fuss with the ECM and such? cause i have an aftermarket ECM with a hypertech chip already, or are the aftermarket ECM easier to deal with? as for the injectors they are Denso Ford mustang ones(thats all the info i can find on them, tried every where online but was told TPI guys use aftermarket Ford injectors cause they spray more fuel) but if i go carbed will i still be able to use the dash gauges or will i have to change to other ones and clutter up the car and make it more obvious that i am running.

91CamaroRS305

iTrader: (2)

BTW its is a weekend warrior, perhaps on a nice day a drive to work, but that is about it, otherwise it will be a bracket car/nifght cruiser

91GTABird

You can use all you factory gauges. The tach might be alittle tricky but it will work.

This is taken from Ray87Z
The ford injectors are rated at a different psi. When you use a higher psi you will get alittle more spray from the injectors dues to the pressure. (its common sense)

Hypertech or other aftermarket chips (ones not burned to your specs) arent worth the money or little effort to swap. If you have the money the Holley Commander 950 engine managment is a great ecm. But if you dont want to spend much then get your own burning tools so you can burn you own proms. That will total like $150, and you have infinite options with it.

If you go carb then the 300* 515" cam wont be much of a problem but i would use about 3000-3200 stall. Youll definitly need a 3.42 or numerically higher gear. I would use something like a Edelbrock Torker manifold, 750-800 cfm carb, and a good flowing set of heads.

91CamaroRS305

iTrader: (2)

i already have have newly machined 202 heads, and i have the iroc borg and warner rear end option, wasnt that the 373 gears or was that 323? and how much does the Holley Commander 950 go for? abd where can i get prom burning stuff?

91GTABird

Whats the specs on your heads.

This link will tell you everything about the Holley Commander 950 ECU

What year Iroc did that BW rear end come out of? The only Iroc options i know of are 2.77, 3.27, and 3.45.

I still dont 100% understand what to get, but im trying to figure it out with out asking to many questions in the DIY Prom forum. But heres a forum to go to,

Prom burning stuff

TKOPerformance

If you're looking to make that kind of power at 6,000+ rpm you should go with 3.73-4.10 gears.

Bottom end concerns depend on how much nitrous you want to run. At 400HP you can easily run all stock stuff, properly prepped (polish the rod beams, ARP bolts & studs, micropolish crank, and chamfer the oil holes with a slight lead in ). Getting into 500-600 HP you need aftermarket rods and a crank. Go with a 4340 forging for the crank and rods. Eagle makes good stuff cheap, as does CAT.

Unless you want to run race gas all the time 12.7:1 compression is way too much. If you use 6" rods you can get away with a little more compression. To run 93 pump gas you will need aluminum heads and 6" rods to run about a max of 11.5:1. 11:1 would be safer, and do not go over 10:1 with iron heads. Compression isn't worth as much power as everyone wants to believe.

The cam is not GM EFI freindly. It's also a bit on the big side. You'd be better off with 280-290 degrees of duration. If you plan to run nitrous it's easier to build a motor that is street friendly and strong enough to take a lot of spray. You could shoot for say 350 HP and build it to take a 250 shot, for a total of 600HP. Then you could run less cam and less compression.

A stock style TPI intake is not up to this task, even with better runners, ect. You'd be happier with a converted LT1 intake, SuperRam, or other short runner intake system for better high RPM power.

91CamaroRS305

iTrader: (2)

the heads are stock 202 160 iron cast heads, i am not worried about compression on cast heads because a buddy of mine has worked iron heads and runs 800-850 HP with a 250 shot of nitrous and has never had a problem, he even told me to stay with iron, but i am not sure whether i am going to go carbed or EFI and the read end is from an 88 Iroc with the otp 4 wheel disc brakes
i was looking at naother cam with a 290/298 degree duration, with a 536/554 lift, and one step below it is 288/298 with 500/520 lift and the pistons i plan on going with are Speed Pro hypertuenectic(or how ever you spell it, the ones above cast but not forged) with a 275" dome (11.9:1 copression) or should i go with 125" with a 10.7:1 ratio?

TKOPerformance

You need forged pistons. That much nitrous will melt hyperuetectics.

I still wouldn't run over 10.5:1 compression on an iron headed motor, even with EFI. Some guys can get away with higher compression with a really loose converter, but I wouldn't recommend it. You are going to run nitrous, so why do you need that much compression? The cylinder pressure is going to come from the N20, so there's really no point in trying to build a super potent NA engine and then spray it. The goal should be to have a street freindly engine that turns into a strip terror when the button is pressed.

SweetS10v8

Id be spending my money on a good set of heads before anything. Heads are what make or break engine power. Have you ever run aftermarket heads?

I started a motor with #882 heads, then switched to fuelie #461 heads, being told and thinking they were the best GM heads(before vortecs were popular) and then swapped on a set of AFRs. The change from #882 -> #461s was cool, but the #461 -> AFR 195s was nothing short of increadible!!

Sounds like your building a motor for somewhat the same use as the motor I used to run (see sig). HEADS HEADS HEADS.....:hail:

TKOPerformance

I run Edelbrock Performer RPM heads on my Blazer. They have 2.02/1.60 valves. I know they are a big part of the reason that motor makes the power that has allowed my fullsize truck to beat the pants off many an unsuspecting car.

All the reading I've done and talkign with people at the track has led me to the conclusion that the AFRs are about the best head available. I read an article where they picked up 50HP using just the heads on an otherwise stock 5.0 Ford. That's amazing.

Eventually I'll be building a motor for my Camaro too. It will probably be around 415 cubes. I'll definately use AFR heads and a roller cam. Either an LT1 or a minram intake. I'm seriously considering building a turbo setup for it too. I've got a lot of other little things to fix before I can even begin to think about that though...

SweetS10v8

I use Flat tops. They offer the best flame travel, then you can buy heads with smaller combustion chambers to adjust your comression ratio to your liking. The 2 valve relief flat tops with 64cc heads come to 10.2:1 which is very streetable, and makes good power.

I think 1 point of compression adds something like 3% HP to a motor, which make a 10:1 with high flowing heads making 450hp a lot more tolerable than a 12.5:1 motor with poor heads making the same 450hp, but having to mix $4.00/gal race gas and retard timing to stop detination.