test
Here's a dyno test that was sent to me today, keep in mind this isn't in any way a streetable set up. Also there was no tuning done on the Tri-y dyno pull so its a pretty equal start in comparision without optimising the tuning.
I have one guy that has a 68' A-body that he races in the stock class. As you probably already know hoe strict that class is. Since almost everything needs to be stock & year correct parts. If any mods are allowed its limited to very few parts at all. So weight, lift, engine size, compression ect are all checked.
The only real things they can change is cam duration but not lift. The exhaust can be anything they want. Gear ratios & stall speeds.
Anyway he spent the day getting a base line dyno test on his motor with Hooker 1 3/4" headers. Then when he got a set of the D-port Tri-Y's the other day he did a dyno test with them.
His engine was tuned & set up for the Hookers. He's ran the car for a long while with the Hookers. He did NO changes other than the headers between dyno pulls. He didn't have time for No timing, jetting tuning on the Tri-Y's. So I don't know if or what tuning like timing or jetting the Tri-Y's would work best with on that motor.
Its the only test so far I have with a 108 LSA. It does show what I had mentioned before on the other tests. That the tighter the lsa gets the more equal the #'s seem to get between the two headers. The test I posted before using 110 - 112 lsa cams showed more or same hp between the two headers tested & 5 - 10 lbs more trq for the Tri-Y's in those tests. Also the wider lsa cams lasted over a much longer rpm range the 4-tubes did.
He did not have the rpm lower than 4500 so I can see if its still a wider rpm rang of power. Since this motor leaves the line above 4500rpms at the track. He may do more tests later on another motor. After a few weeks.
Engine info:
’68 Pontiac 400+.030” – factory 350 hp rating (std – non ram air) - blueprinted
16 heads – no porting – 3 angle valve job only
stock lift cam - .421” int/.425” exhaust – 250-260 degree duration (a secret)
108 lobe sep
cast iron intake – pn 9794234
Q-jet carb
approx. 12:1 compression
Header Comparison
Best Pulls
Jul-06 Jul-06
Pull # 9 12
TQ
.....Hooker Tri-Y
4500 502.3 501.6 -0.7
4600 501.1 491.1 -10.0
4700 489.9 487.0 -2.9
4800 493.7 491.1 -2.6
4900 488.0 485.3 -2.7
5000 488.3 487.6 -0.7
5100 482.2 482.4 0.2
5200 476.5 481.5 5.0
5300 473.1 473.5 0.4
5400 469.4 469.0 -0.4
5500 460.2 457.7 -2.5
5600 459.6 452.9 -6.7
5700 454.5 444.6 -9.9
5800 443.1 440.7 -2.4
5900 436.4 439.1 2.7
6000 433.4 426.8 -6.6
6100 424.1 422.1 -2.0
6200 407.9 408.0 0.1
6300 397.8 395.8 -2.0
6400 387.7 387.4 -0.3
6500 375.3 378.4 3.1
HP
4500 430.4 429.8 -0.6
4600 438.9 430.1 -8.8
4700 438.4 435.8 -2.6
4800 451.2 448.8 -2.4
4900 455.3 452.8 -2.5
5000 464.9 464.2 -0.7
5100 468.2 468.4 0.2
5200 471.8 476.7 4.9
5300 477.4 477.8 0.4
5400 482.6 482.2 -0.4
5500 481.9 479.3 -2.6
5600 490.1 482.9 -7.2
5700 493.3 482.5 -10.8
5800 489.3 486.7 -2.6
5900 490.2 493.3 3.1
6000 495.1 487.6 -7.5
6100 492.6 490.3 -2.3
6200 481.5 481.6 0.1
6300 477.2 474.8 -2.4
6400 472.4 472.1 -0.3
6500 464.5 468.3 3.8
avg 479.0 477.0 -2.0 4800-6200 rpm
There Mr-P I named this one
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