Check this link, this is almost exactly what I want to build but with the performer bored to 2inch and a 454 tbi and the cam I already have is 215/218dur .489/.502lift ona 115 lobe sep. How would my changes affect that same motor?
http://www.strokerengine.com/test383TBI.html

Shouldn't that motor make more power than that?

This is an absolutely wonderful lesson in 'how to implement a failed TBI setup.' They actually build a nice engine: AFR heads, roller cam, roller rockers, forged flat top pistons. Yes, lots of potential.

Then what do they do? Use a near stock TBI intake manifold, some 68#/hr injectors, and a 1-13/16" bore 2 bbl TBI. What a joke. And, what ECM was used? And what tuning was done? My bet is none. Why, second from the last sentence: "and if you don't mind running rich at idle, two 74lbs per hour injectors can make a little more power." No reason to run rich at idle, unless you don't tune it. . .

Now if the site wasn't hung in transferring the rest of the page, maybe I could see the dyno charts. And the spelling mistakes.

As it is this sentence further shows that they are clue less: "Notice how TBI keeps the curve from climbing like a carburetored(sic) motor. This is the 'fly in the ointment' with TBI, this motor with a carb would have made closer to 315rwhp with enough fuel supply."

The only 'fly in the ointment' is their choice of TBI parts. And, they even state the carb would be better "with enough fuel supply." Well, no kidding. How about the TBI? Doesn't that deserve to have enough fuel too?

Slap a real intake on it along with a BBC (2" bore) TBI unit with some fuel, tune it, and that engine will make some serious power.

[/rant-off]

RBob.

I am not impressed, only impressed at how little TBI knowledge they have. Don't get me wrong, its a NICE LONG BLOCK that I wouldn't mind owning myself. Its the Induction system that needs work, like Rbob said. My 312 made 40 RWHP more than their 383 with Cast Iron 305 heads on it and my restrictive 2 1/4" exhaust system. I made nearly 70 more with cutouts open. That is right at 300 RWHP. I made about 20 ft/lbs less at the wheels through the pipes and 10 ft/lbs less through the cut-outs, but what do you expect! They have a smaller-roller camshaft, more compression (0.2:1) and 71 more cubes as well as a longer stroke.

The biggest kicker was adjusting the fuel pressure to 12 PSI with 68# injectors. I run 32ish with NO vacuum to the regulator.

My changes would be either a carbed intake with an adapter or a Holley Projection Intake, a 454 intake, and either cranked up 68 lb/hr injectors or some 454 injectors. Then lots of computer tuning.

They are only down 50 RWHP, 60 ft/lbs, 5 MPG and MUCH dirtier emissions compared to what they could have.