We are finally putting together our 425 Rocket Motor but ran inot a concern today when installing the cam and timing chain (Cam is a Comp Cam 270H -10 shows fits into a 1967 425 and the timing chain is a Cloyes Roller).
When I first placed the timing gears and cam in I lined up the two "O's" 6:00 and 12:00 as instructed. Put when I went to check the degree (using Mondello Degree kit) it was out of spec. So after trial and error (and hours later) I've got it as close as I can but now I'm thinking it's the wrong cam even though it's specified by Comp Cams?
Here's what I've got using the degree kit on the odd side:
#1 Intake 17 BTDC Open, 29 ABDC Close, Max 313
#1 Exhaust 55 BBDC Open, -11 ATDC Close, Max 313 (yes, these are negative numbers on the exhaust close side)
#3 Intake 20 BTDC Open, 35 ABDC Close, Max 313
#3 Exhaust 60 BBDC Open, -15 ATDC Close, Max 313
#5 Intake 15 BTDC Open, 30 ABDC Close, Max 313
#5 Exhaust 55 BBDC Open, -11 ATDC Close, Max 313
#7 Intake 15 BTDC Open, 27 ABDT Close, 313 Max
#7 Exhaust 55 BBDC Open, -15 ATDC Close, 313 Max
Comp Cam Specs
Intake 29 BDTC Open, 61 ABDC Close, Max 313
Exhaust 69 BBDC Open, 21 ATDC Close, Max 313
If I advance it one position I get the following:
Intake 33 BTDC Open, 12 ABDC Close
Exhaust 72 BBDC Open, -27 ATDC Close
(There are negative numbers as it doesn't get to the begining of the ATDC side)
What is going on here? I'm marking every piston at TDC with a gauge to ensure accuracy, performing the test without the heads using the plastic lifter gauge that came with the kit, rotating the engine clockwise from the front of the crank, then reading the numbers. I'm using the first hole (looking front to back) as the intake holes for piston #1 & #3 and the second hole (or closest to the dash) on #5 & #7. Is it possible that I'm dealing with the infamous do I have a 45 degree or 39 degree cam bank, am I screwing it up or are the readings OK? Helppppp!! Thanks.