im midway through building my 355 tpi to drop in my 85 iroc. i want to get at least 400hp out of it. (then it will be the most powerful car at my school, gotta beat those damn rich kids in their porsches!!lol) i already have 10.5:1 pistons and 1.94 intake valves, and massive porting on my 305 heads (higer compression). so far id estimate the power to be somewhere in the early 300s. any advice or suggestions? i know theres more power in there, help a poor 17yr old out. thank you and let the influence of the hot rod elders begin.............


"yea though i walk through the valley of the burners of r*ce, i shall fear no turbo, for the torque is with me"

 

Well since this is the power adder forum, I would have to reccomend no2. I hope you have forged pistons

 

i wish i could afford it. plus nos is illegal where i live. they impound your car and its like a 2000$ fine. besides, thats cheating, i want 400+ of real streetable power. thanks anyway

(although i dont think id be against a small "nitrious insurance policy" just so id be sure to rape the r*cers)

 

You have not given enough info for us to help much here, but here's a reality check. If your car did even have 400 HP with those 305 heads, unless you are putting that power to the ground (i.e. wheelspin) those Porsches are gonna eat you alive.

I am not saying that you can't get those numbers out of your motor, just that it's costly to put that horsepower to the pavement. I have what I would consider a mildly built 355 TPI motor in my Iroc, with AFR 190 heads and I doubt its pushing much more then 300 hp. Yet with Nitto drag radials and a 3.08 limited slip rear, it still boils the hell out of the rear and doesnt launch for s**t. Traction is critical if you want to "beat the Porsches". Sure horsepower is golden, but you gotta get that power to the pavement and make it stick.

For future reference, I would post something like this in the "general" section next time...

 

That's a big 10-4 on the traction stuff, I too have a modded out 355/4 bolt main putting out 389H.P. and 400+ ft./lbs torque and if you can't get it to the ground then you'll be eatin alive. The truth hurts. I thought same thing and only found out hard way that the 3,500 i spent on bada$$ engine don't when races if it ain't moving you down the track. So now I have upgraded suspension and put on B.F.Dragradials for the serious stuff. 13.2@107mph

 

oh im aware that hp does not automaticly lower ETs, that was my mistake, it was misleading. i ment i have to have more power than their cars, but yes i was also planning on doing extensive suspension mods and some drag radials to get those ponies to the pavement. im just looking for advice on how to squeeze the most out of my engine. besides, it just seems so fun to casually mention that your car has 400hp. lol. also, im stuck on a cam decision, i head that anything over a 460 lift is going to make the ECM on my tpi freak out, but i want to get as much streetable hp as i can. what kind of cam should i go with?


(also, im not trying to sound like a smart a** if thats what it seems like, im new to the camaro world, i really appriciate you guys input, you know a lot more than i do, sorry)

 

Ok, here goes. Your not going to be able to reach your goal for horsepower with the 305 heads unless you do really good port and polish work they just will not flow enough. Next real world is you'll need a custom prom to make any real power. How much poor boy budget money are you planning/or willing to spend. Personally I went for torque not h.p. for torque is what makes the vehicle move thru the quarter or even curvvy's. I'm running a flat tappet Cheap from summit $79.95 that came with lifters, it has .488intake lift/ .510 exhaust @114*centerline that keeps vacuum up @18"idle@750rpm. Duration is 284/290. Has very lumpt idle and pulls like freight train from 2500rpm to 5750. Of course you got to realize I've taken all the tips of trade off these websites and put together my beast. That means 2.02/1.6 world product heads though I hear L98's with 1.94/1.5's ported and polished flow quite nicely as I just did it for a friend and that sucker came alive with no prom just done runner matching and freshed up motor with new rings and bearings. He ran 14.1 @98mph after mods. before was 14.5 @95mph. Just glean all you can of stuff you can do for free and then start upgrading as you can afford. Hope this helps.

 

400hp huh? My combo should be about 410 +/- a couple once tuned. Right now its making 388/439 naturally aspirated.

Everything is listed here...

http://personal.tmlp.com/scorp/vette/upgrade.html

... those #s are w/o the nitrous.

 

ok well the guy i bought the engine from custom built it for me (he builds race engines) he did a lot of work to the heads. 194 intake valves, oversized exhaust too but im not sure how big, i have it written down. he absolutly swore on his life that it would be crankin at least 300hp if i put it in as is with a 460 lift cam. now like i say, i still have a lot to learn, so i dont know exactally how hard its going to be to squeeze another 100 out of it. i was thinking roller cam, roller rockers, throttle body, siamesed intake/plenum/runners, maybe some computer mods but im a carburated guy, electronics still scare me. i have access to a full shop with computer diagnostics and all those goodies so ill figure it out. what does everyone think about the siamesing of the plenum/intake/runners? does it work? i have all stock components so theres a lot of metal to be taken off. i wasnt going to cut anything until i checked with some of you guys first.

 

Yes, defiantly do the port work to the plenum, intake, and matching to heads. The key to power is flow, flow, flow. Having the right amount in the right places. Look up search and you'll find plenty of info on here as I did and lots of pictures(cause I'm a picture guy) and it helps to see what the end result should be. Like I said in earlier post, I gleaned all info then dove in. Took me doing the work in spare time and a month later had car on road with awesome response. Old saying is how fast you wanna go is how much time and mooollllaaa are you willing to spend. It helps to do as much as you can for free then put together package that will perform to what you are looking for.

 

hers what you need, my set up dynoed
321rwhp
390rwtq
ran 12.7@111mph
89 iroc 355
mods are
-Trick Flow wedge heads out of the box $900
-super ram intake $1264 with base
-mild cam 470 490 lift 1.5RRs $500
-factory chip no tuning at all homeade CAI
-24#svo
-3:73 gears 5 speed
-52TB did nothing for HP
- 3.5 mufflex and y-pipe $500 3" should work well and hedman LT headers $100
so you don't need the injectors or TB
I ran on 245-50-16 nitto DRs spinning alot and that dyno translates to almost 400hp but 455 torque at the motor witch is great for those street races on the fly
so for $2600 not counting exhaust you can have a fast car for the street, with a bigger cam you could make more HP. I don't understand why i see 3rd gen with similar heads even AFR and bigger cams and Super ram making such little HP my car seems to be the exception.