307 86-442 timing
June 3rd, 2021, 07:49 AM
#1
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Join Date: Oct 2020
Location: Rio Grande Valley, Texas
Posts: 23
307 86-442 timing
My parts have arrived, now i'm questioning timing setup. LG8 motor with 7A heads, no head work.
Cam swap with Comp 42-413-11, which with 7.7 rods will produce lift of 0.478, LSA 110, ICL 106. The grind is Intake -1 BTDC, 31 ABDC and exhaust 42 BBDC and -6 ATDC (4 degrees advanced). 0.050" duration is I-209 E-215 vs The Vin 9 cam of I-194 E-210
I'm wondering if i should install "as sent", or retard the cam 2 degrees, and then engine timing bump to 22-23 degrees. That, or I have a Jet S2 chip that will bump it, i believe, 6 degrees on the ignition timing. The cam is not that radical compared to the original. Ultimately, the intent is to get this at top torque at 2800-3000... car will never see north of 4800 RPM, just looking to get my best power in the street "fun Zone" of 2500-4000.
Should note that the cat has been removed, and the split to the duals has a true Y pipe now which has made a big difference to flow already.
Thoughts from the group?
Cam swap with Comp 42-413-11, which with 7.7 rods will produce lift of 0.478, LSA 110, ICL 106. The grind is Intake -1 BTDC, 31 ABDC and exhaust 42 BBDC and -6 ATDC (4 degrees advanced). 0.050" duration is I-209 E-215 vs The Vin 9 cam of I-194 E-210
I'm wondering if i should install "as sent", or retard the cam 2 degrees, and then engine timing bump to 22-23 degrees. That, or I have a Jet S2 chip that will bump it, i believe, 6 degrees on the ignition timing. The cam is not that radical compared to the original. Ultimately, the intent is to get this at top torque at 2800-3000... car will never see north of 4800 RPM, just looking to get my best power in the street "fun Zone" of 2500-4000.
Should note that the cat has been removed, and the split to the duals has a true Y pipe now which has made a big difference to flow already.
Thoughts from the group?
Last edited by 86 Olds 442; June 3rd, 2021 at 08:02 AM.
June 3rd, 2021, 04:45 PM
#2
Out of Line, Everytime😉
Join Date: Dec 2006
Location: Melville, Saskatchewan
Posts: 9,140
I believe the timing map is already very aggressive, low 60's part throttle. You are under 8 to 1 with that motor, you want to keep the cranking compression and you are adding cam duration. Problem with adding base timing is it adds more timing throughout the curve. Yeah, the factory crossover is horrid, guys gained 1+ second in the 1/4 just adding dual exhaust.
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