has anyone bought a crate motor and successfully put the tpi stuff and everything else back on it? It doesn't look like anything on the blueprint or gmperformance sites are direct fits lots of options for older and newer cars. I'm also concerned the cam and heads won't be a good match for the low revving tpi if it wasn't designed for it. I don't want to go carb but im thinking that might be the least hassle.

 

I just installed a Blueprint 355 for a customer on his 87 IROC. Fit great using the SDPC Vortec TPI base. He quite enjoys it actually. Doesn't make anywhere near it's capability with stock TPI and stock exhaust but we did manage a gob of torque and 202 HP at the rear wheels. Cam worked just fine and has a nice smooth idle. Only changes I made to the tune other than upgrading the car to $6E with all the usual changes was scaling the injectors and some PE changes to get the WOT AFR where I liked it.

GD

 

I have a GM Performance ZZ6 base crate engine that I will be installing a TPI system for my GTA. I pulled the 4 barrel intake manifold and HEI distributor and will be selling those parts off. The TPI setup is an SDPC Vortec manifold, Accel large tube runners and stock upper plenum, all heavily ported. Also 24lb/hr Delphi injectors, adjustable fuel pressure regulator and Dyno Don headers. It all bolts up just fine, but its not up and running yet, so I can't say how well it runs or how much power it makes. The ZZ4/5/6 camshaft works well with TPI and the key will be to port the TPI parts well enough to take advantage of the flow of the Fast Burn heads. I know it's not going to come close to GMPP's 405hp rating with a 4bbl carb, open headers and no accessories, but my guess is that it will be in the 350-ish horsepower range and probably 400-425lb-ft of torque. Plenty of power to have some fun, good reliability and driveability and look relatively stock (unless you know what you're looking for).

I wouldn't do this with all stock TPI parts though. It would be way too restrictive. I've had the Accel runners for years, so I just bought the SDPC Vortec intake and ported everything. If I didn't already have the runners, I would have either used a FIRST TPI intake, or a Miniram.

 

Also, if you are looking for something more along the lines of a stock replacement, an L31 Vortec 350 long block with an SDPC Vortec lower manifold is a good choice. The cam is a little less aggressive than a stock L98, but the heads flow better, so about even or even maybe a slight edge to the L31.

 

ZZ4 here with AFR 180cc heads and a little more radical cam. Had this ZZ4 engine since ~1999 and still runs as well as the day I bought it. Probably 50k on it by now. GM crate engines are well built.

 

On your zz4 motor did you go with the factory TPI? Did it reduce your horsepower? I love the torque I have with my 305 and don’t want to lose it.

 

If you want a stock replacement, dont' bother, just have your existing heads/block gone-through. You'll be infinitely happier. Crap "reman" parts store engines usually have the wrong heads/cam. They often lump TPI and TBI engines together. And the L05 and L98 are different enough that it'll never run 'right' without a tune.

If you are talking about a aftermarket crate engine with some "performance" added, some of them aren't bad. But you really need to look at the cam/head specs to be sure if what youa re getting, and be prepared to get it tuned.

 

Stay with your TPI. Car will be worth more for sure. Rebuild the L98 or if you aren't concerned over a 20hp or so loss..buy a L05 they are cheap and everything bolts right over. L31 is a great choice but the intake will set you back a bit. There are plenty of options though before you give up and regress back to a carb. You have a nice TP I system you should try and keep it. I think you will be glad you did.

 

Stock TPI and stock exhaust you aren't going to make more than 200 at the wheels no matter what you put under them. Need significant intake porting and exhaust to get the TPI up off the floor.

GD

 

I'd say that's a bit over zealous. I admit my car had better exhaust but the tpi was bone stock, it put 230 to the wheels on a conservative dyno. Is exhaust really worth 30+ hp? Edelbrock 1 5/8" headers, a cat, 2.5 intermediate, and an 80 series blowmaster muffler on top of that? Stock exhaust isn't a breather for sure but I don't think I'd claim it's costing you that much on a low revving motor.

 

Probably is worth 30 HP. I just installed a Blueprint 355 dynoed by Blueprint at 397 crank HP into an '87 IROC with the SDPC Vortec base and everything else BONE STOCK (exhaust, headers, etc), and it turned in 202 RWHP on my DynoJet.

Headers and full exhaust on my original 305 LB9 made somewhere in that neighborhood. I made 186 at the wheels and that was the peanut cam flat-tappet engine rated at ~190 at the crank.... which would be about 155 at the wheels through my auto. So yeah - about 25-30 HP for the headers, exhaust, and 1.6 rockers I put on it.

GD

 

Just finishing installation of a HPI 350 from summit . They said it would be a direct fit replacement. Center intake bolts were different angle- so I changed the angle of holes in intake with die grinder. Also gasket matched the intake and heads.