When does custom porting become beneficial?

[F-BIRD'88]

Hot rodding the L98 TPI engines has been done to death. Including porting the stock oem heads and intakes.
Whats the problem? Yes the cross sectional area of the heads and intake is a factor.
Dig up a set of the 083 or 217 castiings or even the 305 version 081's and have at it.
They all need a good amount of porting to get the flow up. Including the CSA.

Exhaust system is critical to getting a fact car result. So is gearing and converter choice.

[F-BIRD'88]

If you want to hop up the stock TPI heads yes "custom" hand porting is required. This is something you can do yourself on these heads.
But you need to do the work. Or you can pay someone to do them. Ya the CSA counts. Making the engine a 383 CID is a popular and smart choice.
Everythiing about a TPI engine and its powercurve is UNDER 6000 rpm. Stop asking the wrong people.

[cab0154]

I just looked up the price of the Profilers, forget that. A set of AFR enforcers will get you where you want to me for 40% less and get you 8mm stem valves and a modern chamber. then you just have to worry about the CSA limitation of the runner.

[KnightEngines]

I just looked up the price of the Profilers, forget that. A set of AFR enforcers will get you where you want to me for 40% less and get you 8mm stem valves and a modern chamber. then you just have to worry about the CSA limitation of the runner.

The AFR enforcers are the same casting as the proheader heads.
Guess which ones are cheaper....

[Tartilla]

Pre-Covid Profiler heads were a great head for a reasonable price. Now they're sky high.

2019 they were $507 each bare. SBC All American.

[Tartilla]

Pre-Covid Profiler heads were a great head for a reasonable price. Now they're sky high.

2019 they were $507 each bare. SBC All American.

[Tartilla]

Pre-Covid Profiler heads were a great head for a reasonable price. Now they're sky high.

2019 they were $507 each bare. SBC All American.

[Tartilla]

Rob, 3rd Gen Camaros were always one of my favorite cars.

Modding the 350 roller sbc should be treated like the restriction plate race engine setup. The TPI will only ever flow so much based on the plenum size and rubber lengths. Add in the use of stock modded parts only, it will only flow so much.

Getting a stroker crank and going 383 is the best thing you could do to get some ponies out of the '87 Z28.

Are you looking for stock cast irons or would stock looking after market work as well?

RHS had some iron Vortecs that would take both manifold styles. Grind off any cast logos etc.

Your 10 bolt rear is going to be an issue if you hook it up, or do you have the 9 bolt Aussie 3.45?

[289nate]

This sounds like an intake manifold problem build.

I have seen my buddy run a stock Ford 93 looking cobra intake, manifold on his 93 cobra. Cut, massively ported runners, shortened welded back up stock to the casual observer. I have seen a Victor Junior intake manifold in a SBF carbureted application with a giant Plenum and a dominator carburetor that looked stock. Obviously ported and welded to an outrageous amount. I have seen weld built up on the top of the inside of an aluminum cylinder head along with the intake manifold to raise a port with epoxy in the bottom. TFS Twisted Wedge ford application. Does any of this fun stuff happen with the TPI Chevy?

[SoCalDave]

Yes. Max effort porting for a max effort build is what I call it. Even if the max effort is for a street build, it is always warranted. Stuff is just more fun that way. However we live in the real world so sometimes porting will do, but custom porting is not on the table.

[RobZ28]

If you want to hop up the stock TPI heads yes "custom" hand porting is required. This is something you can do yourself on these heads.
But you need to do the work. Or you can pay someone to do them. Ya the CSA counts. Making the engine a 383 CID is a popular and smart choice.
Everythiing about a TPI engine and its powercurve is UNDER 6000 rpm. Stop asking the wrong people.

"Stop asking the wrong people." - Truer words have never been spoken. Ive been on this site for 14 years now, and every thread except a couple is all about Tuned Port Injection. I'm a third gen Camaro junkie, since I was a kid. Its always been my "go to" car when I get bored with everything else. You can safely assume I know just about everyone in this community. Ive watched members locally and online modify these cars with varying results since the 80's. If theres a write up, Ive read it. If theres a test, Ive seen it. The problem is there isnt any real data on TPI from an engineering stand point. There never has been. Its all about 2 things, BIGGER ports and SHORTER tubes. We cant do all of that so I need to know some things...
For instance, what are the airspeeds in a TPI system? I assume 250fps in the runners, probably about 285-295 in the manifold and depending on head they can be anywhere from 260-350, maybe more? What makes one modified TPI system only pull to 4800 while others seem to get 5800-6000? ALL USING THE SAME RUNNERS and its NOT just the cam duration.Ive seen it do 5900 with a 220 intake lobe! Do you want to slow the airspeed down so it can make more airspeed at higher RPM's to increase RPM capability of the intake? Or do you want to try to increase the velocity as much as possible to flow as much as possible through a given CSA? Were limited, remember? You have to keep in mind TPI ports PORTED have a MSCA of 1.9-2.1...this is on a ported Edelbrock base without welding. The ASM runners are 1.630 (Not the 1.650 people say) accross. The runners are made with 1.75" OD tubing that have a .060" wall thickness. This gives the entire combination a working CSA of 2.08. Thats the constant that cannot be changed. This means it will flow 260cfm at 300fps. Will a curved circular port flow more air than a rectangle port, meaning, can I run a bigger head below that runner? Do I match flow potential or do I match velocity?

As for the cylinder heads, I choose to run iron with a modern chamber. I like the vortec heads but the SDPC vortec base will only port to a similar size as a stock ported base. Were talking about 245ish CFM MAX. This means MAX flow through the head will only be 220cfm, NO MATTER WHAT. Thats a deal breaker. I'd like to see 245cfm at the head or more. But again, I am limited to an intake runner of 2.08 CSA. I am looking at the Dart 165's, the Bowtie small ports, the Mexican vortecs and possibly even the stock ones if the intake really shows to be that limited.

[RobZ28]

Hot rodding the L98 TPI engines has been done to death. Including porting the stock oem heads and intakes.
Whats the problem? Yes the cross sectional area of the heads and intake is a factor.
Dig up a set of the 083 or 217 castiings or even the 305 version 081's and have at it.
They all need a good amount of porting to get the flow up. Including the CSA.

Exhaust system is critical to getting a fact car result. So is gearing and converter choice.

I have factory 083's on it. The problem is I want to take this car a step further than just bolting stuff on and hoping for the best. I want to do it right.

[RobZ28]

Yes. Max effort porting for a max effort build is what I call it. Even if the max effort is for a street build, it is always warranted. Stuff is just more fun that way. However we live in the real world so sometimes porting will do, but custom porting is not on the table.

I agree.

[RobZ28]

This sounds like an intake manifold problem build.

I have seen my buddy run a stock Ford 93 looking cobra intake, manifold on his 93 cobra. Cut, massively ported runners, shortened welded back up stock to the casual observer. I have seen a Victor Junior intake manifold in a SBF carbureted application with a giant Plenum and a dominator carburetor that looked stock. Obviously ported and welded to an outrageous amount. I have seen weld built up on the top of the inside of an aluminum cylinder head along with the intake manifold to raise a port with epoxy in the bottom. TFS Twisted Wedge ford application. Does any of this fun stuff happen with the TPI Chevy?

Yes, youre on track now. Its a major intake manifold problem. Yeah we have some stuff but nothing close to the likes of what the Ford guys have. When the LS swap became affordable, all the manufacturers killed off anything SBC that became unpopular, like the TPI stuff. I am stuck buying older stuff online.

[RobZ28]

I just looked up the price of the Profilers, forget that. A set of AFR enforcers will get you where you want to me for 40% less and get you 8mm stem valves and a modern chamber. then you just have to worry about the CSA limitation of the runner.

About Chinese made stuff… I’d rather not if I can help it. I don’t want to get into politics but I am not happy with the way our country has been going. I choose to avoid China if I can. Thank you