86redIROC

Quick overview of my build: 86 IROC 355, trickflow 175cc 1.94/1.50 56cc chamber heads, 10.5:1 compression, Comp xfi 268 flat tappet cam, AS&M runners, Ported TPIS plenum, edelbrock base manifold, descreened MAF, Hawks ram air boxes, Stainless works long tube headers, 3" magnaflow exhaust, no cats or emissions, custom tune.

Im thinking of sending the edelbrock manifold out to high flow injection to be stage 4 ported for $250 and the trickflow heads to Total Engine Airflow for a cnc port job for ( they end up with 200cc intake runners and new 2.02//1.60 valves) $950. So Im trying to debate the potential power gain vs money spent? Comments?

Jim85IROC

iTrader: (2)

Personally, I wouldn't do either. The base isn't the most restrictive part of a typical TPI setup, the runners are. Just porting the base without doing something about the runners isn't going to amount to much. That said, hogging out those heads to 200cc is just going to kill your torque, without adding any horsepower thanks to the restrictive TPI.

Keep the heads you have and swap the TPI for a First TPI or stealth ram. It will be a much more beneficial upgrade for less money.

86redIROC

I did switch to the bigger AS&M runners, My understanding is the First setup has slightly shorter and wider runners? Is it that much better than a ported edelbrock base and the AS&M runners? Also, why are so many people running AFR 195's on 355 TPI's? Would that be overkill on the TPI if the 200cc's are?

cuisinartvette

The first runners are way better than the ASM

What are you expecting out of everything?

What youll get is a set of heads that breathe better and an intake system that still runs out of breath

Do a lot of TPI bases runners etc yes youll get a gain but to be honest if you get heads that breathe real well step up to a shorter runner intake alltogether.

Put it this way seen way too many that sink a ton in a TPI system only to buy a better intake within a yr or less. Sell if off and buy a converted LT1 intake or used Mini

86redIROC

I want to stay with TPI. Love the low end torque. I also want to stay with MAF which I believe you need to run speed density with the First system? I still believe porting the edelbrock base will lead to some power increase. And I think porting the trick flows will also help a bit. I realize for that kind of money I could go to a shorter runner system but want to keep it somewhat original looking etc. I figure heavily porting the base and cnc porting the heads should be good for another 40hp?

cuisinartvette

If TEA is doing the heads sounds feasible as far as your gains they do nice work.
Get that base done as ***** out as you can then.
Your gains will only be as good as the job on the intake if that makes sense. Keep us posted

built91Z28

Just a personal observation. I see a lot of TPI guys say they want to stay with the TPI because they love the low RPM torque. I think a properly built street motor will have plenty of low end torque. I know I do and my motor still revs to 6300. And I'm running a Vic Jr intake. A restrictive intake isn't the only way to have low RPM torque.

Jim85IROC

iTrader: (2)

Then don't have TEA hog those heads out to 200cc. An intake runner that big is going to be lazy at low RPM and is not going to provide the same low end torque that the 175s will. I think the 175s are a much better match for TPI. Porting those heads to a 200cc intake is going to allow substantially better flow at higher lift, which is only going to be realized in a motor that's got a big cam, and adequate airflow into the heads (read: Not TPI), and is going to provide more air than the motor can possibly use at modest RPMs. The only place you'd find gains would be at higher rpm, which the TPI won't support. Just a guess, but with the 200cc heads and a cam that offers any hope of taking advantage of those heads, I would expect that you won't see a horsepower benefit until 4,000 rpm or higher.

Orr89RocZ

iTrader: (20)

I dont think the heads would totally kill off low end power and torque when done right, but I dont think its worth sending them out for 950 to get converted to 200cc 2.02 valved heads. Alittle hand clean up and maybe a good valve job could see some power but you really need to get that induction setup opened up. The larger heads would certainly take over after 4000 rpm but as it sits the TPI is basically done with peak power by 4500 and only after that will the cam/heads dictate if power holds on for awhile. Your heads are kinda too small for a good 350 TPI motor but 200cc's are alittle large for a typical sub 5500 rpm 350. A good compromise would be open up the heads for something like a 2.00 LS type valve and final port volume of 185-190's cc. Keeping velocity profile fairly fast will still build cylinder pressure.

Thats one of the reasons why AFR heads work so well. The ports are pretty fast in velocity profile so they tend to fill cylinders well at lower rpms but can choke a motor out on higher rpm setups because of air separation over the short run radius in the port. Too high velocity will choke a motor out.

TEA does good work and the 200cc stuff will no doubt run well on the motor, I just think for 950 is not a great bang for the buck since your running flat tappet and long tube runners. IF you could do a roller cam and keep duration somewhat short but jack up the lift to get a fast valve action, you will see good gains in power. Siamesed runners for higher rpm will love the 200cc heads. With TPI over the 0-4000 rpm range, you may not see a huge increase in power....

I'd get the base ported and leave it at that. The runners will now be the restriction but AS&M's are pretty big tubes so they still will do well.

86redIROC

I like the idea of just getting the base ported. i believe the trickflows flow 242/178 cfm at .500 and the edelbrock base flow around 210 to 220 cfm unported. So getting a bit of restriction out of the base should jump overall power. For $250 thats not too expensive.

Orr89RocZ

iTrader: (20)

I'd try that first to see what it does, retune and go from there. If you need more power I think you'll find that in the heads and better cam design...hyd roller conversion would be worth it IMO

86redIROC

I forgot, besides the lifters what do you have to change in a roller conversion?

86redIROC

Ok, so the more I think about it, im leaning toward Mini Ram with Comp 280xfi cam and having TEA cnc the heads. I think that combo with the rest of my mods will get me in the low 12's.

Orr89RocZ

iTrader: (20)

If your car is setup right and fairly light that combo with roller cam conversiob would get you high 11's with ported heads

86redIROC

Love the TPI look and low rpm peak torque on the street but when it comes down to it the Mini Ram eats it alive from a flat torque curve and high HP perspective. Plus Mini Ram makes me way way faster than any of the new stock Gen 5 Camaros, Mustangs, Challengers.

bestracing

Those flow numbers are measured without other parts hooked up to them, just the flow bench and the head or just the bench and the lower base. Porting them out will increase the flow numbers on the bench but good numbers on a bench don't always add up to better performance numbers. I've seen heads that have lower flow numbers out perform other heads with better flow numbers. The flow needs to match the whole system work properly.

A cheaper option would be is to polish the base and remove the rough casting pits and lines

You would need a cam button on the front to keep the cam from walking forward. Not all timing covers work with cam buttons.