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Good morning Wade, as always I (and others) appreciate your efforts in doing this kind of stuff, your awesome bro! I am still trying to get some cash together to have my Super Vic Ported, was going over the date and the stock S Vic was #3 on flow compared to all of the stock and ported intakes. I would guestimate that a properly ported S Vic would yield the highest flow of any intake?
It's already known a Dorman LS2 will easily outdo a stock LS2, only because stock LS2's are slugs.
Not arguing for the LS2 oem manifold. My last lS6 setup was more mild than the LS2 setup in process and made 376whl hp thru the oe OLS2 The new intake setup is a ported LS2 doorman. Just ready to see all my flow numbers and calculations turn into dyno verified ponies...
Hi Chad, the Super Vic definitely rocked in the flow numbers. With port matching I'm sure it would pick up quite a bit more. That's probably the best intake for this set of heads. I talked with Tony Mamo and he mentioned the intake ports on my 250cc GMPP's are really too big for an exact port match with a plastic intake. A metal intake is another story. I hope all is going well my friend.
We're just getting over a round flu at our house and that has slowed down my update.
Land Speed Cylinder Heads developed a couple of valve jobs for this set of heads so we could pick what was the best match for the heads and my budget. I passed on the high lift VJ version that saw 335 cfm at .650 lift - it was so tempting to change directions with the build but none of my other parts are matched to 7,500 rpm screamer.
There were several issues I wanted improved or fixed on the GMPP's before putting them on an engine. There was a nasty stall on the intake side at .650 lift. A good head should be able to hit 1 inch lift and not stall according to Darin Morgan and several other experts. Brett at Land Speed agreed and fixed that issue with the heads Likewise, the exhaust flow wasn't what I wanted. We could band-aid with more exhaust duration but the right thing to do was fix the exhaust port.
Brett cleaned up the bowl area and used his trick custom designed Xceldyne exhaust valve. The port remained untouched and the heads picked up 20+ cfm of exhaust flow
Brett set the BTR Platinum springs up and shimmed them for 165/400 pounds which is perfect for the sort of cam we will use. This was about ,15 to 20 more than unshimmed.
Given the heads had been decked .030 by the previous owners, we had to open the chambers up some for a possible for a 4 inch stroker build. We needed to shoot for ~64 cc just in case I have to settle for a stock bottom LS2 short block. Brett nailed it perfectly and the chambers are 64 cc with the heads decked .032 total for a fresh surface.
Ferrera intake valve 2.04 ended up at 96 grams. Under cut valve stems. Working the chambers Hand finished and worked chambers End result with new valves Ready for that 4.030 bore LS2 stroker Fresh deck
Light Blue - The flow test numbers the seller advertised.
Blue -What the heads actually flowed.
Pink - Flow with the revised valve job and chambers.
I'm happy with the overall improvements made. I suspect they were worth ~15 to 25 hp over where the heads were previously depending on the cam and intake etc.
Of course this was all geared towards squeezing the max airflow out of the Peak Ported 90mm LS6 intake.
Green - LS6 intake flow with the original GMPP heads
White - TPiS/LPE 90mm LS6 intake w/GMPP heads
Blue - Peak ported 90mm LS6 intake w/GMPP heads
Pink - Peak 90mm LS6 intake new mid-lift VJ GMPP heads
When I saw the flow results my first impression was we've reached the point the LS6 runner is really maxed out. I'm going to have get a new intake if these go on a stroker.
Brett felt with the 250cc intake runners the heads should work well on a 4 inch to 4.070 bore motor with a 4 inch or 4.125 inch stroke. Beyond the 4.070 bore it would be more ideal to have a bigger intake valve. He also said I should consider at least a 102 Fast LSXR if these heads are on a 400+ cube engine.
After seeing Mamo Motorsports Composite Intake Manifold Sale it seemed like the logical time to consider a different intake manifold. Darth's Mamo ported MSD is one of the most impressive LS manifolds I've seen. Tony took the time to discuss the build, considering the heads and my overall budget. We decided a Mamo ported cathedral Fast 102 LSXR would be the best intake for my bread & butter 402 build.
Being at the tail end of GP, I'm last in line to receive the manifold. So in a few months there should be one last installment of this manifold test with a Mamo ported 102 LSXR intake manifold
Last edited by 99 Black Bird T/A; 03-17-2019 at 07:51 PM.
I was also wondering if the factory style intakes were just holding all the heads back in your comparison. The work on your heads is just incredible. The turned valve stem is something i had only seen on seen on cheater race engines (that had to keep stock valve size to be legal). Really pretty work there.
...
Being at the tail end of GP, I'm last in line to receive the manifold. So in a few months there should be one last installment of this manifold test with a Mamo ported 102 LSXR intake manifold
You'll be in front of me. Mine's not going on anytime soon, so I told him to put me dead azz last.
84FSP, Thank you. Brett at Land Speed really stepped up and did a fantastic job with these old GMPP's
Intake manifold = restrictor plate
All most all of the cathedral plastic LS intakes other than a well ported MSD, ported LSXRT and maybe a ported LSXR seem to cut off 35 to 50 cfm of airflow for all of cylinder heads I've been able to have tested over the years. Even the metal ones like the BBK for that. I guess it's the nature of squeezing the intake into such a confined space. The Super Vic with some porting looks like it has real potential. Of course flow numbers aren't everything just a starting point really.
LS Cathedral cylinder head dyno and flow numbers
There's a set of $1,350 TEA ported LS6 heads that don't flow quite as well as several big ticket aftermarket heads. However, there TEA LS6's are within 3-5 hp of the very best and often made better average hp.
Bigsapper - lol, I didn't know that
Which intake did you order LSXR, MSD,??
Thank you for the information. I'm next to last It's all good, I'm happy it worked out so I got in on the Mamo ported intake GP
I think we'll be very happy with a Tony Mamo ported manifold.
I ordered a FAST 92 Mamofied; also take off the logos. I also sent a silver blade LS2 TB for porting.
That sounds like an excellent set up. Very smart sending the TB for porting as well. What's the cost of getting the TB ported too if you don't mind me asking?
Originally Posted by wannafbody
That seems like a pretty nice gain in flow from the reworked heads.
Thank you
You'd love to see what Brett at Land Speed Cylinder Heads can do with a set of LS7's or a set of Trick Flow's Even the Coyote 5.0's & Hemi's are impressive - wink.
The bomb in my opinion are the fully ported LT1 Gen V direct injection cant'd valve heads. Makes me want to sell all my junk except the 91 RS and get a new Z06 Vette or 1LE SS and go mod crazy.
Hey Wade, ever heard of Abrasive Flow Machining or Extrude Hone? Been getting some prices for having the Super Vic ported and ran across this process. Seems as though the prices for each are comparable with both running around $750 give or take. I have only seen photos of the process, nothing that I could put my hands on but I am very curious about it. Ever seen it or touched it?
That sounds like an excellent set up. Very smart sending the TB for porting as well. What's the cost of getting the TB ported too if you don't mind me asking?
No idea. He did one on my C7. It was $390 but IIRC that included the TB. $200, give or take?
Hey Wade, ever heard of Abrasive Flow Machining or Extrude Hone? Been getting some prices for having the Super Vic ported and ran across this process. Seems as though the prices for each are comparable with both running around $750 give or take. I have only seen photos of the process, nothing that I could put my hands on but I am very curious about it. Ever seen it or touched it?
Chad
better yet........has anybody extrude honed a plastic LS intake yet ?
Chad, my direct experience with extrude honing is limited to a set of 02 fbody manifolds I picked up in the for sale section a long time ago. It was pretty impressive how the extrude hone process had thinned the cast iron. The finish was smooth and it looked like it should flow better.
Later, I ran the idea of extrude honing a Q-jet dual plane aluminum intake manifold for a small block Chevy by a friend who is a good engine builder. Normally he was well informed with his understanding and explanation. He said for a port fuel injected application the extrude hone process could work OK but generally not as well as a well done hand ported manifold.
For a carbureted engine he said extrude honing typically a terrible method. The intake runners are left too smooth and the air fuel mixture separates more than normal on the way to the intake valve. With the air/fuel mix have to travel as far as it does in a carbureted manifold application sometimes gas droplets form by the time the mix hits the intake valve and that hurts power. The fix is to go back and add slight texture to the runners so the air and fuel don't separate. So again in his opinion it was best to have an experienced porter do the intake manifold.
I was pretty disappointed because my idea of extrude honing and hogging out an aluminum Q-jet manifold for a 383 stroker went up in flames. Ending up using a Dart dual plane which he hand ported along with a set of Dart Pro 1 heads that he ported in a Dart 400 build.
Haven't read up on extrude honing since etc so my "information" maybe dated or inaccurate.
better yet........has anybody extrude honed a plastic LS intake yet ?
Extrude hone was very popular with the pushrod 5.0L croud back in the day.. (especially with the crazy long runner stock and GT-40 intakes) but if you are trying to go max effort then cnc and hand porting is the way to go... then the ports can be shaped to what you want to do with the engine... not just whatever the putty material takes out of the casting... as far as plastic...I remember that they use really hight pressure to run the putty thru.. I dont think the plastic would hold it.... but then again im going from memory from 25 years ago....
ASRoff, that's a fascinating bit of history about the GT-40 manifold, thank you for sharing it. I bet your right about the plastic runners being a little to fragile to extrude hone. It really doesn't take all much to split a Fast runner into and break it along the seem. I've got a couple like that.
Well, looks like Extrude Hone is out of the picture. I'm ok with that all though I loved that idea of the extrude process, looks like it would be a kickass thing to do. But I guess when it all comes down to it a hand job is best.
03-08-2019, 06:49 AM
Likewise, the exhaust flow wasn't what I wanted. We could band-aid with more exhaust duration but the right thing to do was fix the exhaust port.
