HooWybrow

Hey guys, I'm no stranger to a small block, have had a few gen I's that made 500+, fuel injection is fairly new to me in terms of making power.

I've got a 98 S10 with an L31 swapped in from a 98 fullsize. It's got the elusive poppet valves and my cylinder 4 one may as well be pooched.

So here goes, I've got access to a very cheap, complete TPI. Through reading I have found they're not great at the top end, and I would be in an extra $400 buying the proper lower section for my Vortec motor. That, or am I able to run old style heads on this motor? Ideally, aluminum heads would be great to relieve some weight off the front of the old girl.

I've been searching around and think I like this cam:

http://www.summitracing.com/parts/cca-08-503-8

My question is, is the TPI setup worth spending the money on? I've found a few others for a LOT more money invested (GMPP ramjet, etc). If I can save some on the manifold setup, I have that much more to play around for cyl heads, etc.

Thanks in advance guys.

bowtienut

iTrader: (1)

You might find some better advice and examples at a place like this:
http://www.fullsizechevy.com/forum/g...n/performance/

Not a lot of experience with that motor on this forum, but I do have a little experience with the L31, so I'll offer this:
First, 400 whp means you won't have much left of an "L31". About the only thing I'd keep, with that target in mind, is the shortblock, and then you might as well start with any old SBC Gen 1 block.
Yes, the heads are excellent as far as iron heads go, but to take them from their ~250 whp baseline capability to what you want, your money would be better spent on aftermarket conventional Gen 1 aluminum heads and avoid the Vortec intake manifold limitations. so yes, old-style heads are the way to go if you're serious about that goal.
You're right about the stock injection needing to go, even if you were to stick with the L31 heads. Even the GM upgrade to the poppets will get you nowhere toward your goal.
And for 400 whp.....forget TPI. It's too much of an "rpm choke" to get you near 400 hp without ridiculous money and mods heaped upon it.
If your goal was more like 300 rwhp, then you could make it happen with the Vortec heads and modifications to the manifold. Check out the forum I linked above and search under vortecstroker screen name. The stock manifold quits about 5500 rpm, so figure 325whp as the limit with a 383, and 300 whp with a 350/355. That cam you linked would easily get you to those numbers, but may be a stretch for 400 whp.

Edit: There are also a few threads on this forum in the "Tech" and "Engine Swap" sections on L31 buildups:
http://www.thirdgen.org/techboard

HellTeeOne

I'm taking a shot in the dark here as I'm not all that familiar with TPI stuff. But wouldn't a TPIS Miniram, a set of 30# injectors, 58mmTB, a good custom HR cam, a set of the best 200-215cc TFS or AFR Gen1 SBC castings ported by LE or AI, on top of a healthy shortblock with the requisite longtube headers and exhaust get him his number?

Of course, this assumes the compression ratio, PCM tuning, ignition, etc. is all in order and up to snuff.

bowtienut

iTrader: (1)

Yes, it would. Easily! It's either something along those lines, or lower his goal if he's retaining much of the L31 setup.