B-body TBI

[Chiecto1]

I've got a 91' olds custom cruiser that I transplanted some kind of 5.7 into back in highschool. I was told it was a truck motor but I found it had a roller cam in it. According to what I found, truck motors had flat cams. I wanted to get some more HP and more low end torque. I'm trying to find a good replacement engine for this combo. I found The GM 12530283 which seems to be the vortec block. Seems pretty good but will that cam be good got a b-body wagon? I was looking into the possibility of swapping the cam for one with a different power band, maybe in the 1500 hp range. I've been through all kinds of sites and everyone's answer is "LS swap" it, or "it's not worth it". So I'm here to ask this knowledge base for help.

Im not going to be drag racing this car, I just want something that's a good street car with the ability to torch the tires. I still have the stock 700r4 with the factory stall. I've got the stock exhaust with no cat and just a muffler. I was thinking about changing to some decent long tubes if the performance is there. The rear end is stock 3.08, I may change it to 3.73 if I have the time.

jerry

[Six_Shooter]

Trucks came both flat tappet and roller. I don't remember what year the change over happened, but just because it's a roller motor doesn't mean it's not a truck engine...

Anyway, any cam that will have an advertised useable RPM range of around 1500 RPM (which is what I assume you meant when you said "1500 HP"...) to about 5500 or so will be good if everything else is stock or pretty close to. The cam is not the only component to get a corporate engine to make power, it's just one of the parts. Ported heads (or Vortec heads) will make a difference as well. The only issue there is an intake that will work under the hood of a '90's B-body, due to the cowl overhang, and the different sized dizzy base (larger dizzy opening in intake to make it possible to stab or remove a dizzy with the engine in the car... dizzy matches the larger opening). Vortec heads require a Vortec intake or an intake modified for the taller ports.

Look at working on the top end before worrying about swapping out the bottom end. Engine MAKE power with better top ends, better bottom ends just HANDLE the power. ;)

[Chiecto1]

You are correct, I meant 1500 rpm. Yes, I understand I would need a vortec Intake with the swap to vortec heads. I know the TBI heads flow like garbage. I was thinking about using a vortec carb intake and buying the adaptor plate or making my own plate. My original plan was to go with vortec heads and use the L98 cam which is what I believe was used on the 9c1 engines thus giving me a solid platform for finding parts. From there I found a bunch of serviceable ECU chips. But, before I spent the money on the L98 cam, would it be better to go with a different cam and custom tune?

[Fast355]

For a nice 350 in a street application the TBI heads can work very well. Especially with the stock torque converter and gears. The Vortec heads really do not have anything to gain until over 4,500 rpm. My old TBI G20 van had a F-car LT1 cam in its 350 TBI. It made more torque than my Express van did with the 300 HP marine cam.