Flyer

iTrader: (1)

What are ya'lls thoughts on this setup on a big cammed 408. This would be using an intake elbow and stock TB too.

dirt track racer 81

iTrader: (45)

why stock tb??

TurboGibbs

iTrader: (6)

Here are my results with a mild cam'd 370
https://www.performancetrucks.net/fo...d.php?t=399574

From driving the intake i'd say that it shined above 5500. I would only think about using it again if it was on a 402+ ci and a big cam. It would probably do much better on a big motor. More air flow with cubes and cam would probably bring the sweet spot down considerably. I had to turn my 370 7200 for it to feel good but the L76 intake after 6500 it is flat.

Flyer

iTrader: (1)

I'm kinda disappointed and surprised that the carb intake didn't do as well as the l6 intake. I figured it would have been just the opposite.

The motor I'm putting it on is a big cammed 408. No FI, maybe some nitrous down the road, but not right now for sure.

TurboGibbs

iTrader: (6)

But the L76 starts to run out of breath above 6000 on a 370 and the carb intake is just getting started. If you run a high stall (~3500+) and a big cam that is going to pull up top then I'd see a good advantage to going with the carb intake. If the L76 is running out at ~6000 i'd imagine it would start to run out ~5500 on a 408.

Flyer

iTrader: (1)

DId you notice though, the carb style intake made less power even after the L76 started running out of air? It looks as though that's beneficial all around.

TurboGibbs

iTrader: (6)

Yes, but I feel that is partly due to I was running out of cam by the time the Carb intake came in.

Did you see this test. The carb intake did make more on the high end.http://www.gmhightechperformance.com...ads/specs.html

If I still had my carb intake i'd let you borrow it for a test on a big cam 408 vs a L76. None of the LS1tech boys are using it really since it won't fit under their hoods. I'm not a fan of the carb intake really (hell, look at my dyno) but I do feel it would do pretty good on more cubes with a 240-250* ish cam and shifting at ~7000. It would be interesting to see the comparison.

Flyer

iTrader: (1)

Interesting ... I'm beginning to wonder if I'm headed in the right direction still. I already have the heads and intake, I just have to get all the extra stuff to make them work.

I feel for sure it's going to add a good amount of power over the stock 317 heads and truck intake still, but I wonder if it's going to be as good as I think it's going to be.

Quik

iTrader: (7)

no it wont. if you get a ported set then youll see some numbers. they seem to work well on 6.0/6.2 motors in stock form. 4" strokes need port work to produce similar numbers as 6.0/6.2s

Flyer

iTrader: (1)

Comparable flow number:

L92 heads first ...

Quote from StreetnStrip (quotes removed to save format)

Richard@WCCH Did the flow testing of the new L92 heads.

I just finished flow testing a new stock L92 head. All I can says is…….WOW! What a nice part.
I’d like to publicly thank StreetnStrip for the opportunity to test this head.
The test head has casting number 5364. Here’s the tale of the tape……..

4.030” test bore
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Int. 74.9 109.4 154.4 193.5 225.3 252.8 274.6 292.7 308.8 321.0 328.7 326.6 310.0 316.6
#1 Exh. 63.6 97.9 126.1 148.7 162.3 178.6 189.6 197.6 205.5 210.7 214.6 217.8 221.2 223.5
The intake was tested with a radius plate and the exhaust was tested with a 2 ˝” stub pipe.

4.155” test bore
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Int. 73.8 108.7 153.2 192.6 225.2 253.6 277.0 296.7 313.0 326.0 335.8 326.9 327.3 317.1
#1 Exh.61.1 97.9 125.7 148.1 162.0 179.5 191.8 200.1 205.9 213.3 218.4 220.9 221.9 223.2
The intake was tested with a radius plate and the exhaust was tested with a 2 ˝” stub pipe.

Exhaust port tested without pipe (4.155” bore).
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Exh.63.1 94.7 121.1 140.6 156.9 165.8 176.1 182.8 187.9 191.4 193.7 195.6 197.6 199.5

Valve dimensions:
Intake = 2.160” X 4.870” X .314”(8mm)
Exhaust = 1.590” X 4.920” X .314”(8mm)

Seat/throat diameters:
Intake = 1.870”
Exhaust = 1.355”

Volumes:
Intake runner = 260.6cc
Exhaust runner = 90.0cc
Chamber = 69.8cc

A few observations………. These heads have the best seat/port lineup for an as cast GM head that I’ve seen. Their casting precision is VERY good. The fit and finish of the valves are very nice as well. The intake port is large, especially the area above the short turn radius. The intake cross section starts at 3.1sq/in at the intake flange and grows to almost 3.7sq/in forward of the guide boss!
I’m a bit disappointed with the exhaust port flow. IMO it needs to be at least 25 peak cfm better. I’m sure the engineers at GM know what they’re objective was and they were satisfied with the final product but I think for hot rodding especially blown applications, the exhaust port needs to be improved. Looks like head porters will have something to do after all………
I understand that there is a company working on a 4bbl carb style intake, but I’ll leave the intake manifold subject for another thread.

Happy hot rodding.

Richard


L92 408 first results....


https://ls1tech.com/forums/showthread.php?t=626547



L76 intake flow numbers(Special thanks to Rick at WCCH for the info )
https://ls1tech.com/forums/showthrea...5&page=1&pp=10