I'm new and need help!!
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Joined: Oct 2006
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I'm new and need help!!
I am replacing my 305 lg-4 engine with a chevy 400. Here is the question. What is the "biggest" cam (recommend one if you please) that I can use and STILL RETAIN THE STOCK COMPUTER! I plan on using the 2055 headers and a single 3" exhaust. The car currently has an Edlebrock 3701 performer intake and a stage 2 hypertech chip that I will reuse. Other notes:
700R4 with a 3.23 rear gear.
The 400 will have 2.02 / 1.6 valves otherwise stock vintage 70's.
By the way the car is an original 70K survivor, no winters, black with gold TA. No cracks on the inside and original paint. I love her as much as my 2001 Bullitt.
The lg-4 ran a best of 9.98 in the 1/8 with a 1.908 60' time
I want her to beat the Bullitt's best of 13.8 (1/4) at 99MPH.
Thanks to all.
700R4 with a 3.23 rear gear.
The 400 will have 2.02 / 1.6 valves otherwise stock vintage 70's.
By the way the car is an original 70K survivor, no winters, black with gold TA. No cracks on the inside and original paint. I love her as much as my 2001 Bullitt.
The lg-4 ran a best of 9.98 in the 1/8 with a 1.908 60' time
I want her to beat the Bullitt's best of 13.8 (1/4) at 99MPH.
Thanks to all.
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Welcome aboard thirdgen.org.
I sure hope your 2.02/1.60 heads aren't stock 400's. You'd honestly be better off with your LG4 heads.
As for the cam, about the only concern is high overlap causing O2 sensor confusion at low RPMs. The computer isn't making high-order calculations, mainly mixture ratio and spark advance. If you keep the LSA in the 112-114 range, you can run quite a bit of duration - up around 230 @ .050". I'm running a ZZ4 cam, and the computer is as happy as a pig in a mud puddle. At sea level, it would run well under your 13.8 @ 99 with "just" a 350 and 2.93 gears. So, a cam in that range (flat tappet, of course) should do the job for you in a 400 with decent heads and 3.23 gears (assuming you can get it to hook). I ran a Crane 2050 Compucam in the 305 before I went with the roller block 350, it was a little wild on the 305 but would be much tamer in a 400. I looked at various Comp cams on summitracing.com, one that looks promising is the XM270, which is a "marine" cam, but it has the LSA, duration, and lift that should go well in a 400 with factory heads and the Performer intake.
I sure hope your 2.02/1.60 heads aren't stock 400's. You'd honestly be better off with your LG4 heads.
As for the cam, about the only concern is high overlap causing O2 sensor confusion at low RPMs. The computer isn't making high-order calculations, mainly mixture ratio and spark advance. If you keep the LSA in the 112-114 range, you can run quite a bit of duration - up around 230 @ .050". I'm running a ZZ4 cam, and the computer is as happy as a pig in a mud puddle. At sea level, it would run well under your 13.8 @ 99 with "just" a 350 and 2.93 gears. So, a cam in that range (flat tappet, of course) should do the job for you in a 400 with decent heads and 3.23 gears (assuming you can get it to hook). I ran a Crane 2050 Compucam in the 305 before I went with the roller block 350, it was a little wild on the 305 but would be much tamer in a 400. I looked at various Comp cams on summitracing.com, one that looks promising is the XM270, which is a "marine" cam, but it has the LSA, duration, and lift that should go well in a 400 with factory heads and the Performer intake.
