Looks like most bugs are ironed out. Hoping to not only make it to the track Saturday but also maybe make a couple tuning changes between runs (this is a test & tune day). In short combo is 454.070, Dart Pro 1 alum hds, Air Gap, 850VS, 233/236, .600/.610 hyd roller, 112LSA, 10/1 CR, 2500 stall, 3.73 gears, 275-60/15 DR's. 1.75x3" headers into 3" X-pipe full exhaust.
Base settings are 22* intial, 36* total w/ 10* vac adv can for 46* total w/ vac adv.. Prior motor was 10.4/1 w/ same cam and never detonated even with prior 16* vac adv can. Ironic, this motor detonates w/ only 10* vac advance. So, guessing this motor is just a lot more efficient. {FYI, heads were cut when I got them, originally intended for Shafiroff crate motor, new in boxes. Advertised and marked as 114CC. I did not CC them. Am assuming these are 114CC. I know they were cut, but now not totally sure how far. hindsight, I should have CC'd them}. FYI, I have not done cylinder pressure tests. May do one cyl on each bank just for baseline. Carb is box stock 850VS, 78/82 jetting, 4.5/3.5PV. I did have to install 1/2" open spacer on the AirGap to get the fast idle screw to clear the intake, but will probably remove it and cut the screw Other than the mild knock at high vac, I don't have any driveability issues.
Will make first run as is with air cleaner intact for baseline. Only intended change from weekend cruiser will be the DR's. Thought I would play with timing first. Maybe disconnect the vac advance and push timing to 38* total. I kind of doubt I would see any benefit of anything over 38* with alum head open chamber motor and .210 dome piston. I know the old closed chamber iron head motors liked as much as 40* timing, but doubt that much timing is needed for this setup, especially considering this motor's propensity to knock at only 46* total on 92-93 pump gas.
Any sugestions?
Base settings are 22* intial, 36* total w/ 10* vac adv can for 46* total w/ vac adv.. Prior motor was 10.4/1 w/ same cam and never detonated even with prior 16* vac adv can. Ironic, this motor detonates w/ only 10* vac advance. So, guessing this motor is just a lot more efficient. {FYI, heads were cut when I got them, originally intended for Shafiroff crate motor, new in boxes. Advertised and marked as 114CC. I did not CC them. Am assuming these are 114CC. I know they were cut, but now not totally sure how far. hindsight, I should have CC'd them}. FYI, I have not done cylinder pressure tests. May do one cyl on each bank just for baseline. Carb is box stock 850VS, 78/82 jetting, 4.5/3.5PV. I did have to install 1/2" open spacer on the AirGap to get the fast idle screw to clear the intake, but will probably remove it and cut the screw Other than the mild knock at high vac, I don't have any driveability issues.
Will make first run as is with air cleaner intact for baseline. Only intended change from weekend cruiser will be the DR's. Thought I would play with timing first. Maybe disconnect the vac advance and push timing to 38* total. I kind of doubt I would see any benefit of anything over 38* with alum head open chamber motor and .210 dome piston. I know the old closed chamber iron head motors liked as much as 40* timing, but doubt that much timing is needed for this setup, especially considering this motor's propensity to knock at only 46* total on 92-93 pump gas.
Any sugestions?
