nwalton29

iTrader: (7)

Whats the max timing on a 445 CID w/ 245 ETP cath port heads with 12:1 compression. Running 93 octane?

BLK02WS6

iTrader: (2)

Gonna depend on the cam - and therefore the dynamic compression ratio... only the dyno can tell you...

nwalton29

iTrader: (7)

Would you think 27 deg is feasible in that large a motor?

BLK02WS6

iTrader: (2)

I think that is probably kinda high for that compression. I had 12:1 in my 408 with a big cam that lowered the DCR a good bit, and it made best power/torque at around 25 degrees... Don't think more cubes will make much difference on the timing. Like I said, you're gonna have to get it on a dyno to find out where it wants to be...

nwalton29

iTrader: (7)

Well it was dynoed, three pistons fried a little later. I'm thinking too much timing. I wont go back to that tuner.

BLK02WS6

iTrader: (2)

The rule of thumb is to always start low and work up - especially with something like that...

RAMPANT

iTrader: (17)

I was going to say 23-24 with that compression. We had 27 with my 455, but it was only at 11.1:1 and 94 octane.

My 412 was at 12.4:1 and would only take 23 degrees for best power on 94 octane. It also preferred an AFR of 12.4. My 455 likes 12.8.

BLK02WS6

iTrader: (2)

Same here - mine wanted 12.3-12.5 AFR...