tylerc

So I swapped a 350 carbed engine into my Camaro. It has a quadrajet and a dual plane weiland intake manifold from a o-reilies crate engine. Are these worth a crap as far as horsepower goes, or is there a lot of power to be had swapping to another one?

sofakingdom

iTrader: (1)

Depends on whether it's the bottleneck to the motor or not...

If it's a 8.2:1 smogger clone with smog large chamber 70s heads and dished pistons, in front of a stock torque converter with highway 2.something gears, probably not. Other things limit the performance of the total package more than the intake.

If the motor is well-built for horsepower, with decent compression, flat-top pistons, good heads with smaller chambers, and the car has gearing that lets the motor rev, etc. etc. etc., then maybe it is.

THe first situation is the more likely.

Intake manifolds being as cheeeeeeeeeeeep and eeeeeeeeezie to swap as they are, and being a big pretty thing that sits right out there in the open just BEGGING the uninformed to swap it out, it's EXTREMELY rare to find that being the weakest link in the CAR'S overall performance. Same for the carb, unless it's broken. I'd suggest directing your attention elsewhere.

blackbmagic

Its more than enough, for stock heads. They start getting restrictive or so around 400+hp. The RPM air gap would be a step up. And then smaller single planes.

My buddies 383 makes ~400 to the wheels with a dual plane from GM performance.

There is a difference though. Dual planes will give you more power down low with a basically stock motor. Single planes have their advantages in the upper rpm range. Without knowing the specs on your motor cant say for sure.

I would say aside from headers and good flowing exhaust, heads/cam would be the weakest link. There are some big power gains to be had from heads/cam swaps.

tylerc

I really don't know that much about the motor in it but I would assume it isn't anything too special. Def iron heads and I would assume a low-perf cam. Like I said its whatever O'Reilies sells as a crate engine for a 74 Monte Carlo which I haven't been able to find much info on. I traded an old non running car for the running engine and car. It is a stock converter and I believe stock gears however the last guy did put a locker in it.

Assuming its a 'smog copy' engine, what kind of gains could you get from just a decent cam? How about low priced heads and cam? I saw a set of vortec heads for 160 bucks and even though I know I would need a new manifold I have been thinking of going that route.

blackbmagic

Put it this way, I had a 70's smog 350. I bored it 0.030 over, changed from dished to flat top pistons upped the comp ratio to 9:1. Port job and deck on heads (not sure on comp ratio now). Comp custom ground 480lift 108lsa flat tappet cam, Performer intake and 650dp holley. As well as bolt on's like hooker comp shorties, true duals with chambered mufflers.

I dont have dyno numbers but this all upped the hp from a smogg rated ~165hp to an estimated 375+hp.

tylerc

~200 hp from pistons, heads, intake and cam?

Apeiron

200 HP from changing nearly every part of a factory low-output engine.

Of those changes, the heads by far had the most impact, followed by the cam and pistons. The intake would have had very little to do with it.

five7kid

iTrader: (14)

If you still have the 70's smog heads, I seriously doubt you're getting 375 HP out of it. Porting and decking smog heads was money poorly spent.

blackbmagic

Why so judgemental? Intake has almost nothing to do with the performance gains but if you refer to his earlier post he wanted to know what could be done.

Stock heads were removed, and I replaced them with a set of clean 882 heads I had. A guy I know from the shop owed me a favor, decked them when I got them back I did screw in studs, and a port job that cost me the price of some porting tools and bits. Not my first rodeo. But I think they are still technically considered smog heads non the less.

five7kid

iTrader: (14)

Not judgmental, realistic. If you had a dyno sheet, that would be a different matter. But, you said "estimated".

Yes, I would consider 882's "smog heads", and although you didn't say earlier exactly what heads you had, I assumed the odds were on my side to assume that's what you had. The chances of getting 375 HP out of a 350 with 882 heads at 5500 RPMs (the limit of the Performer intake) is somewhere between slim and none, regardless of what you did to the heads.

Most likely his O'Reilly engine has the same or similar heads, so I don't want to give him the false impression that 375 HP is possible out of his engine with those heads. Hence, my response to your statement.

Having said all that: tylerc, as others are trying to say, don't bother replacing your intake manifold until you do heads and cam (and exhaust, if you don't already have headers and a free-flowing exhaust system).

tylerc

Going to flip the car after I repaint/redo the interior and play with it for a while so 1k on a set of heads is out of the question. Cam for 150 bucks perhaps, what hp could I expect with a cam swap? I could always port the heads myself, I have all the carbide bits/die grinder to do it. Def not tearing into the bottom end though. Those vortec heads for 160$ are still kind of calling my name.

Yeah the exhaust is okay but not what I told the shop to do, no cats, shorty headers, 2.5" back to a turbo magnaflow with a cutout right before it. I told them to do 3" and was a little pissed when I went to pick it up.