jimmyray
Well-Known Member
- Joined
- Jul 17, 2007
- Messages
- 948
- Reaction score
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I was recently mocking up my 408, after I recently tore it down. With the crank back in and damper installed, with a dial gage, I determined true TDC to double check the damper marks. Low and behold, the damper was off by 5 degrees! Effectively increasing whatever i thought my timing was by 5 degrees. Since I thought I was running at 34 degrees total, I was actually at 39! Although I never heard pinging or detonation noises, even with 87 octane, this could not have been good.
My motor combo was:
408 Eagle cast crank, Eagle rods, KB Hyper pistons, all from Hughes
9.6:1 compression
93 Octane gas
mild port/polish on Edelbrock al perf heads, closed chamber, fresh valve job
M1 single plane airgap with gasket match (heads too)
Carter TQ - .102 & .161 jetting, 1.5 primary
Comp roller .544/.541 236/242 110 centerline
FBO ignition, ditributor curved to 16 inital, 34 total @ 2900 rpm
Hooker comp 1 5/8" headers (dented bottoms on driver side, naturally) 3" collector
3" pipes into/out of welded Summit 3" mufflers into a-body tips
4000 9.5 Dynamic Convertor
727 manual reverse
3.73 sure grip in a narrowed Dana
Race Weight 3400 + 200 driver = 3600 lbs total
The best I ever got out of the combo was a 12.13 @ 110. By the time I took it apart, after 130+ runs and 6500 miles, the blow by was enough to push off the EGR breather and blow oil out of the dipstick tube, and it was losing water bad.
Thoughts?
BTW, the Damper was the summit $89 job.
My motor combo was:
408 Eagle cast crank, Eagle rods, KB Hyper pistons, all from Hughes
9.6:1 compression
93 Octane gas
mild port/polish on Edelbrock al perf heads, closed chamber, fresh valve job
M1 single plane airgap with gasket match (heads too)
Carter TQ - .102 & .161 jetting, 1.5 primary
Comp roller .544/.541 236/242 110 centerline
FBO ignition, ditributor curved to 16 inital, 34 total @ 2900 rpm
Hooker comp 1 5/8" headers (dented bottoms on driver side, naturally) 3" collector
3" pipes into/out of welded Summit 3" mufflers into a-body tips
4000 9.5 Dynamic Convertor
727 manual reverse
3.73 sure grip in a narrowed Dana
Race Weight 3400 + 200 driver = 3600 lbs total
The best I ever got out of the combo was a 12.13 @ 110. By the time I took it apart, after 130+ runs and 6500 miles, the blow by was enough to push off the EGR breather and blow oil out of the dipstick tube, and it was losing water bad.
Thoughts?
BTW, the Damper was the summit $89 job.