What is your budget and how much work are you willing to do? Bolt on stuff? tinker?

 

around 3k maybe more, and just bolt on,

 

Your 1991 Camaro will have 300 hp at the rear wheels as it is now.

A pair of aluminum heads, 700 CFM carburetor and intake manifold will add about 40 hp, headers will add about 20 hp and a camshaft with .490” valve lift and 230 degrees duration will add 20 hp . The peak hp will be at 5,500 RPM so you will need to change the rear end ratio to 3.73:1 or 4.11:1 to be successfully driven on the street.

 

The Vortec heads should work well, but the cam is only 224/230 @ .050 and the compression is 9.1. It should be a very nice combo for a daily driver in a Camaro with headers and a low restriction exhaust.

If all you want is a little more horsepower, a higher duration cam would probably be the first step, but don't get carried away since you only have 9.1 compression. You would have to ask Blueprint if these heads would can handle 1.6 ratio rockers, since that may also help. The 600 cfm carburetor is probably too small if you want over 400 hp.

The downside of a cam-only upgrade is that most of the additional horsepower is going to come in at a higher RPM, so you need low gears and loose torque converter to keep the RPM in the power band.

I might first try more timing and bigger carburetor, since they are simple steps, but you might need to put it on a dyno to determine the best tune.

Bruce

 

A custom built carb or custom built cam, together would likely get you in the 430ish range would get you there without blowing your budget and keep the smooth power curve.

 

if the engine is rated at 373 fly wheel hp and you want to get up to 400 rear wheel hp, (i think that is what you are striving for) then you are going to have to pick up about 100 fly wheel hp to achieve this, with the 9-1 compression i think you are going to be limited with cam selection, maybe a small blower or nos would be a option,

 

So i just acquired a 1991 Camaro with a Blueprint 350 ---->*https://www.summitracing.com/parts/mll-bp3501ctc1/questionsanswers/

At the crank its rated for 373hp
What mods can be done to this existing motor as it comes to hopefully reach 400+ WHP

To get 400 hp on the rear wheels requires you produce between 480 to 580 HP at the crankshaft depending on how efficient the installation can be made, a lot of this is the fitment and effectiveness of the exhaust system. This is getting into a zone where the parts inside this engine are not up to the task with any reliability if you expect this to stay together for any reasonable time on the street. The cast crank, stock strength rods, hyper-eutectic cast pistons, etc. are not up to the task for very long at this power level and the Vortec heads are, well, in over their head.

This is a nice engine for its build point but lacks the internals for making 500 crankshaft horsepower and staying together.

Bogie

 

I went over to Summit's site and read all the questions and answers about this motor and here is my conclusion...…

13-14" intake manifold vacuum at 900 rpm's.
9.1:1 static compression ratio for use with regular pump gasoline
Hydraulic flat tappet camshaft (motor is said to have a little lope to it, so it's way more cam than I would use with a 9.1:1 static compression ratio.)
High-rise, dual-plane intake manifold similar to Edelbrock 7101 Performer RPM, so that's maxed out for the application.
600 CFM Holley 0-80457SA carb
Engineered for max hp of 357 @5500-5800 rpm's, max torque of 397 ft/lbs @4500-4800
Engine builder recommends 2000-2400 stall torque converter

What this tells me is that with the exception of a good set of equal length, long-tube 1 5/8" headers, the motor is maxed out as far as bolt-ons. You could go bigger on the carburetor, but you probably wouldn't feel it in the seat of your pants. Stay away from those cheezy short-tube block hugger headers, you might just as well run cast iron manifolds. Plan on paying 500 bucks for a good set of headers, another 500 for a good converter and 500-1000 for rear gears and a locker, professionally installed.

I would be thinking of using a 10", 2500 stall converter and minimum 3.73:1 rear gear. If that does not wake it up to your satisfaction, rig up a turbocharger and blow 5-6 psi into the motor with a good water injection system to help prevent detonation. The internals of your motor will not tolerate even a little detonation.

What Bogie was explaining is that you in your 1st post, you were asking for 400 WHP. There are 2 ways to rate horsepower in the automotive industry, flywheel horsepower (FHP) and rear wheel horsepower (RWHP). Since the torque converter, transmission, U-joints, differential gears, axles, wheels and tires will absorb roughly 20% of the power that is available at the flywheel, a car with 400 RWHP might have 500 FHP.

I would not invest any more money into cylinder heads, without completely upgrading the internals of your motor.


.

 

Save your pennies for a 6L LS engine with a head and cam swap.
Drive your car till you can afford the swap..but be warned!
500fwhp will SHRED the stock axle
500fwhp will SHRED any stock trans short of a TH400
500fwhp will REQUIRE a better cooling system
500fwhp will make you want bigger brakes

Me? I'd put a 750 carb on it and a 75hp 'WET' shot of Nitrous. I'd get ahold of Dyno Don for some of his awesome 3rd gen 3/4 length headers and I'd only hit it in high gear. That gets you up to about 450fwhp (assuming your 373hp claim is correct).

 

I'd replace the heads with AFR or RHS and lean toward 10:1cr and with a custom roller cam, professional built carb go play with it and not worry about a HP figure. Smart shopping will get you a convertor too for your 3k budget.

 

https://www.vsracing.net/catalog/shopping_cart.php ($450)

https://www.ebay.com/itm/Spectre-Industries-9849-Carburetor-Plenum-/131226240249 ($110)

Blow Through 750Â*|Â*Carburetor Solutions Unlimited ($975)

https://www.ebay.com/itm/Innovate-M...id=718953046&hash=item41cb228406:g:hVoAAOSw6GBZcc0Z:sc:USPSPriority!13901!US!-1 ($170)



Another $300 of exhaust manifolds, pipes and flanges. Buy a $300 welder and have fun if you don't already have one. Boost reference your fuel pump and a $50 return-less regulator.

Totals $2300. You'll need another $3-500 of misc crap, but under $3K and you'll make your 400whp goal be a thing of the past.

 

A couple of the better deals you're going to find on headers...and their stainless to boot!

I've bought a couple sets of these Ebay headers for other cars and the quality is quite good, bordering on excellent. 9 or 10 mm head flange is stout, tubes or almost mirror polished finish, and all welding is TIG welds, very nicely done. They are imported, made offshore somewhere, (India/China/Indonesia), but quality surpasses Hooker, Hedman and FlowTech if you want to be honest.


https://www.ebay.com/itm/Camaro-Fir...rs-Y-Pipe/232936394558?fits=Model:Camaro&hash=item363c174f3e:g:94kAAOSw4A5YysuJ

https://www.ebay.com/itm/Chevy-Cama...d-Headers/332826200006?fits=Model:Camaro&hash=item4d7dfcc7c6:g:tjMAAOSwZ1BXdurJ

 

quality surpasses Hooker, Hedman and FlowTech if you want to be honest.

I was thinking the same thing about mine, plus they cost less than a new driver's side factory manifold on my car.