I have a 85 corvette with a carbed 355. the car weighs 3400 lbs with driver. I mostly street drive it and occasional drag it. I was wondering if you could look at the combo since it's apart and give any suggestions.

355
9.3-1
speed pro hyper pistons
Dart iron eagles (180 cc) intake runners
weiand stealth dual plane
holley 750 VS
Elgin cam ( installed 4 deg adv.) 224-234@.050 112 LSA 107 ICL 495-510 lift with 1.6
turbo 350, 2500 stall
stock D-36 with 3.07 gears
1.75 headers
cheater kit . i plan to spray 150 on it.

best et so far 12.76@107 1.85 60'


My main concerns are too big of headers,possibly too big a cam?

thanks

Mike

Welcome to the forum.
The headers are too big IMO.
The cam for the gear and motor looks ok.
A 750 double pump would help the car leave harder, other wise it looks fine to me.

my only concern with the 1-5/8 headers is the spray.
do you think those smaller headers will be ok for 500 motor HP ?

Mike

Headers are def. overkill, probably losing a little there. I would also maybe look at upping the compression a half point or so with that cam for it to be real 'happy'....something like a head gasket change to a .015 steel shim if you are currently running a composition gasket could get you .4 or so increase in compression. I wouldn't hesitate to put in 3.42s either, but I don't think the 3.07s will hurt you that much.

i could definatly raise the comp. I had no detionation on 93 at 36 total.

i plan to go to 3.45 this winter.

I see a few issues with your combo... so I guess since you asked headers... I will start there. I think with spray the larger headers will give you a bit more power, but they will definetly hurt you off the bottle. For a street car or a none serious race car I would run the smaller ones.

I also agree the compression ratio could come up a bit. And the rear gears are killing ya.

My last bit of advice is about your hyper pistion selection with the use of nitrous. In theory you can run a 150 shot on hypers so the experts say, but IMO you are playing with fire. You will be best served keeping things a bit rich and take out a shade more timing or run a sperate fuel system with race gas. Also since they tend to expand and contract more you will want to open up your ring gaps a bit too. If you get detination or have problems you will most likely destroy the bottom end and possibly the heads. Hyper's don't melt or crack like other pistons on spray... they shadder and they destroy a motor in a matter of milli-seconds.

I'm sure someone will pop on and say I have been spraying on hyper pistons since whenever and have never had a problem, but IMO it isn't worth the risk. You never sleep well at night after a nitrous problem destoys a motor. I know all too well.

thanks.

i will bump the comp. a touch. i'll probably end up at 9.5-1 with iron heads, my cranking compression before was 180.

I ahve a seperate fuel system for the spray and run 118 in that with 93 in the tank. I also pull 2 deg per 50 HP. I also run a 1 step colder NGK plug.

thanks.

I'll try smaller headers and the gear is coming this winter.

just as a note you can have better e.t's and more mph thru the traps if you shift the nitrous down the rpm range. if the motor is happy turning 6500 rpms and this makes the best e.t and mph on the motor then nitrous will be better served to shift at 5500 rpms.......nitrous produces better times in the lower rpm range.....

mike i dont know anything about funny gas but as captaincrunch says you will be playing with fire with the pistons and he is also right about a hyperteck piston they shatter and can do much damage to the hole motor when they let go

thanks guys.

I shift the car at 5700 on motor and 5200 on spray.