Ok, I've been over analyzing this way too much, but hey, it's a hobby, and it's kinda part of the fun! Final decisions haven't been made, but here's what I'm thinking. L31/Vortec longblock, with the necessary head work for a little more lift. I'd also like to use a LTR TPI, and I already have a set of ported and matched SLP runners and plenum. if the SDPC vortec base was as good as the other manifolds, that'd be it. Decision would be made. Obviously it's not. Here's my question for those of you who've actually tried and worked with that Vortec TPI manifold:

Do you think that the manifold can be port matched to the runners and heads enough to NOT be the restriction?

I understand that while the vortec heads are good, they're not magic. I also understand that the long runners themselves inhibit high end power. I fully understand what I'm leaving on the table and the cost of doing so. I also don't mind the labor for porting. I've read JerryWho's thread about customizing the vortec manifold, and that's NOT what I want. I'm nowhere near capable of that anyway. I'm talking about doing some garage port matching myself, and bolting it up. Thoughts?

 

hey whats up remember me... i bought you spindles somes time ago in north carolina off rock quarry road...

anyways i have been through this myself and i was upset by the results...personally i have never been a fan of that manifold its simply too much work for the little gains you get out of it... the heads are great but its really defeating the purpose of the gain if you put heads that a abit better than l98 heads and a manifold thats flow worse than the better flowing edelbrock unit using stock heads, not to mention that your limited in head choices with the vortec base... honestly i would sell of all my tpi parts and keep the vortec heads and buy a vortec first intake from ken.... that tpi would flow better than any normal port job you can do on your own and have the advantage of the better flowing heads without killing that with a lousy manifold... the first is only a 1000 bux.... you can get more than half that selling your intake.... so for 400-500 more bux you can have a MUCH better intake system that looks stock and have vortec heads.....

 

Yeah I remember you! ...and I've been following along with your FIRST build over the months. Good job!

Honestly, I just don't like the look of the FIRST. I know it works, I just don't like the look. If there's one thing I've decided on, it's the GM style TPI. ...I've driven vehicles with L31 vortec set ups (not TPI) and the power and cost make it the right choice for me. If I was gonna go carb, or HSR, then it'd be a done deal. But of course, we're having THIS conversation, so of course it's obviously still up in the air!!!! I know the Vortec base doesn't flow, but why? Every always says it doesn't flow, but it's better if it's ported. Well of course it's better!!! ....I guess my point is that we all know the long tube runner TPI isn't the best. It does what it does. I'm OK with that. What I'm not ok with the vortec base out of the box. My question is can I get out the die grinder and make it work, or it still a lost cause?

 

THere is a vortec version of a HSR, if you choose to go that route.

 

"My question is can I get out the die grinder and make it work, or it still a lost cause?"

Sure can if that is the route you choose to go. There is at least one if not more comprehensive threads on the subject. We are talking some serious work in one of them.

 

I ran a fully ported stock base and plenum with SLP runners with the dividers ground about halfway down on a flat-top 350 with TFS G1 heads and a 218/228 cam. The G1 heads flowed around 240cfm at cam lift,,, which is around 10cfm more than Vortec heads. The best I could run with that combo with temps in the high 80s/low 90s was 12.9’s – switching to a box stock FIRST dropped it right at .4 seconds.

I would suspect the TPI Vortec base could be ported to flow a little better than the stock TPI base, but the base flow in and by itself isn’t the problem. When you bolt the runners to the base, the percentage drop in flow is pretty bad – even if you do a little off-set or “skewed” porting to help the base to runner transition (which I rarely if ever see). However, if you’re not racing the car, then you’ll probably be more than happy with the feel you get from the ported TPI/SLP combo and the Vortec heads – especially if you’re planning on running a converter with less than a 2400 stall speed.

FYI – The FIRST and the HSR ran practically the same ETs on my combo, but had very different power characteristics. The FIRST still had most all of the low rpm characteristics as the GM TPI and almost that of a dual-plane intake on the high-end. The HSR had decent low-end,, almost that of a dual-plane with the top-end pull of a single plane. I preferred the FIRST, but if I raced the car more than driving it,, I’d probably picked the HSR – the FIRST was a little hard to launch while all you had to do with the HSR was heat the slicks and floor it.

Hope that helps.

 

Abubaca,
I'm doing a Vortec TPI build right now also. I clamped the base to my work bench and I plan to start making aluminum shavings tonight. My plan for porting the intake is to remove as much of the injector boss as possible, port match the base to the runners, and open up the short side radius of the intake ports to straighten the airflow path. I don't know how much the porting will help because I'm not wasting my time putting the manifold on before I port, but I will have before/after dyno and 1/4 mile times, with the only engine changes being a swap from 461 fuelie heads to 062 Vortecs, unported Accel base to ported SDPC Vortec base, and the addition of 1.6 rockers. My hope is that I gain 30 horsepower, which will bring me to 280rwhp.

If you're interested in following the thread, you can find it here:
https://www.thirdgen.org/forums/engi...tpi-build.html