Hey car guys and gals. I just finished up my build a nice 1991 Camaro RS. Where I live there isn't a dyno close so could anyone estimate how much i might have? Small Black 327 with a casting number 3858174 (came from a corvette). Forged pistons (ICON Performance Pistons). Ported and Polished 305 heads. 350 tbi system and the manifold is ported. Last is tubed headers Runs great and I got it up to 150mph and had more to go [:

 

350 rwhp. Around that

 

What camshaft?

Ive never seen a TBI hit over 300hp at the crank - not saying it cant happen, I'd love to see it. Just never seen it... Id imagine youre at 225-275 crank horsepower. Camshaft makes all the difference here. What size valves are in the heads?

At least with the 305 heads your compression should be decent. Should be a fun car even if its not making a ton of horsepower.

Take it to the drag strip, weight it and get a trap speed and you can get a VERY close estimate of the crank horsepower number.

 

Haha, not a flying chance in hell. His whole setup is bottlenecked to say the least. It won't necessarily be a turd, but it's definitely not going to be fast compared to what it could be with a few adjustments.

 

Somewhere in the 2x if hes lucky

 

It honestly feels like I'm just getting bashed for my hard work and passion for building cars.. All I know is the cam is the stock cam that cam in the 3858174 and GM estimated specs 300hp to 350hp. Does the forged pistons help my hp? I'm unsure the ported 305 heads valve size. I do know it has a 3000 stall on it. I'm just a young man and learning as I go. I'm also planing on buying a single turbo kit soon. What adjustments do you suggest? I have an edelbrock 1406 carb but it back fires so that is why I have the tbi on now. but could have been my timing?

 

The GM "specs" for back when those motors were new, were not related in any meaningful way to any measurable aspect of reality.

They changed from "gross" HP "ratings" to "net" ones in about 1972.

The "ratings" nowadays are bad enough; before 1972, they were even worse. Typical "ratings" dropped to around 2/3 of what they had been before, when the "new" system was put into effect, WITHOUT ANY CHANGES TO THE PARTS.

A typical "300 HP" motor from the 60s would be "rated" around 210 - 225 HP using the "net" "ratings" system.

If your motor has been rebuilt, then what HP it was "rated" at before, no longer applies. Since HP isn't a function of the block casting number or the sheet metal (or fiberglass) that the block was wrapped in 40-odd years ago, there's no way to throw around "Vette" and a casting #, and connect that somehow to your engine's present power output.

There were several "stock" cams that you might have a replica of. Most common were the 929 and the 151. Tell us which one it is, what the piston specs are, what size valves are installed in the heads, and other MEANINGFUL things about it, and maybe we can make a guess.

Meanwhile, as you would have learned had you been paying attention in high school physics class, HP (power) is a measure of work done (energy released) per unit time. Work, or energy if you prefer to call it that, comes from fuel. In order to release the energy, you need air. The amount of air that passes throung something per unit time is called "flow" in this hobby, and is usually measured in cubic feet per minute. (that being a convenient combination of units; 1 HP = 33,000 ft-lbs per minute, and RPM is revolutions per minute) Therefore, an engine's power output can be predicted with a high degree of accuracy, if the flow of the parts is known.

The throttle body that comes on a 305 flows around 400 - 450 CFM. That's roughly enough for 260 - 275 HP, given typical pump-gas engine ability to turn the chemical enrgy in the fuel into mechanical work (mostly limited by the compression ratio). Doesn't matter how many CID the motor has, doesn't matter how bad the gearing is (which is why it'll do 150 mph but takes a half-hour to get up to 65 mph), doesn't matter about "Vette", doesn't matter about "150 mph"; NOTHING else matters.

Therefore I'd say if you have the whole thing COMPLETELY maxed and and working PERFECT, you're getting around 260 - 275 HP at the crank right now, which should be good for around 200 - 210 at the rear wheels with that power-sucking unnecessary mistake of a transmission you have.

Science is a wonderful thing.

A chassis dyno is great too. All the bragging and tough talk in the world seems to kind of disappear on those. They can be a very humbling experience. Not to be insulting or anything, but I suggest you concetrate on bragging less, and more on accumulating more facts. Given that you're in Indiana, you're almost certainly within EASY driving distance of a chassis dyno. They're EVERYWHERE. Go talk to a PROFESSIONAL racer and find out where one is. If I was the betting kind, I'd probably be willing to bet there's AT LEAST ONE within 20 miles of your house, in fact.

I'd also suggest that you'll get FAR more bang for the $$$$ by building a better motor than that old 60s thing, than some "turbo".

 

Some better heads, good dual plane intake and that 1406 carb would go a long ways on this.


But if you're happy with it as is then enjoy it!

 

I agree with your first sentence. Let me say I am sorry you where being treated as you where. I hope you hang out and continue this thread. I promise you there are a boat load of guys on here that can help you.

I do remember stock 327's that where 300hp at the f/w. Those are basically using the stock 350/400 cams from the 60's/70's. There is a 350hp 327 that had more compression(much better gas then) that used a L79 cam. These are old tech on the cams. The L79 was mainly made for more compression,stick shift,higher rear end gear ratio cars.

A good cam for you would be comp cams H268-10. Higher rear end ratio,slightly higher t/c stall.

A misconception from yrs ago was we thought by changing to 202 valves and attempting to port stock heads with limiting materials to work with on stock head's ports that we did make significant differences. We thought the 202 valves alone was the answer. That isn't now supported by flow bench testing. I fact the bottle neck was the port size that couldn't be opened up enough. Thus the aftermarket heads come onto the market,well that and other features the aftermarket heads offer.

I suggest a step approach would be Vortec stock production heads with the comp cam,slight T/C stall,and rear end gears would be a nice combo.

Next would be the same cam etc and the Vortec Bowtie 180CC heads.

 

OK. Care to guess who came up with those gross hp rates in the dyno rm??. Well that could have been.......naw,then maybe it was........nope, opps it was me!!!. A conspiracy??.

Support the O/P in his build.

Man that sofa must have developed a spring sticking ya. Sure have gotten grumpy over the last few posts.

 

I do have the L79 cam. I really enjoy the car and wouldn't mind street racing a bit. The point about why I went with the 327 is because it's not your typical engine when you pop the hood on your 91 camaro rs. I understand it's not a 500hp power house. But I feel that it won't be much til i reach 400hp. That's my goal

 

Nobody was bashing.

You wont see 400hp with the factory TBI, no matter what else you do.

 

www.tbichips.com

www.dynamicefi.com

 

How so?

Nobody can tell diddly about "327" just looking at it. It's a small block Chevy. You can make ANY 262.5, 265, 267, 283, 302, 305, 307, 327, 350, or 400, or any hybrid or overbore or stroker of those, look totally indistinguishable. They're basically all the same to the naked eye.

 

Sofa is not bashing you.. he's being honest. We're also being honest in telling you that 400 HP is not necessarily a walk in the park.. you definitely need to carefully put things together in order to get to that mark.

Your 327 is not going to be anywhere near 400 based on what you have done to it like mentioned before. Does that mean we don't support you? No, it doesn't.. but we don't support having your head in the clouds and spoonfeeding you BS output numbers because eventually that information will travel to someone else wanting to build something.

305, 334, 327, 350, 383, 396, 406, 434, whatever is out there.. it's been done before a million times. Just because you don't see it often doesn't mean it's necessarily better. In my opinion - you punched yourself in the nuts over 23 potential "free" cubic inches you could've gained from a 350... or even more had you built a 400 or something or that nature. My 355 is among thousands of others out there in these thirdgens. What makes it different? I actually built my motor, and that's all I care about. The next time I'll most likely build an even bigger motor (that someone has probably done fifty million times). Do it for yourself, not because "it's different".. Just a thought.

 

Three ways of coming up with numbers.In a dyno rm,chassis dyno,and at the track. Those numbers don't lie. Anything else is speculation and some of it is from having built it before,but still much guessing going on.

 

Nuh uh. The 350 will be distinguishable. It will have a faint aurora of heaven and gold radiating from it.

 

That's only with the LS1. Jesus made those.

 

With Chuck Norris driving anythings possible. What a team!