360 Advice Needed - Autocross / Street Engine Build
Hi Guys, I'm looking for some advice with my project, in particular cam selection and static compression ratio.
It's a 72 demon, that was previously an all original restoration. It will now be a sleeper type build, used for street driving and AutoX / HPDE days.
I want to keep the engine looking like it could have come from the factory, no chrome / bling, and will have these key parts as limitations:
- Original air cleaner assembly (cutout in back for airflow)
- 360 exhaust manifolds (ported on the short turns, and polished inside)
- Stock valve covers (will spacer to clear rockers)
- Turbo style Dynomax 2.5" mufflers, dual exhaust
- 91 octane pump gas
So far, I have the following setup on the engine:
- 360 block, 0.030" over
- KB107 pistons, +0.005" deck height
- 0.032" squish, closed chamber heads
- Edelbrock heads, OOTB RPM
- RPM Air-Gap Intake
- Edelbrock 800 cfm carb
- Comp Cams 275 DEH, Hydraulic, 219/235 @ 0.050", .462"/.482" lift
(previously installed to work with exhaust manifolds)
- 1.5 roller rockers
- Static Compression ~11:1
The car has a 3000 stall converter, 3.91 gears, and will have 26" tall 245/45/17 RE-71R tires.
This engine will spend most of it's life at 3000-5000 rpm, but needs to idle when stuck in some traffic. I don't care about vacuum inches, it's manual brakes & steering.
Questions:
- With this cam / compression combo create too much cylinder pressure? (for pump gas)
- Should I change to 1.6 ratio rockers for more lift?
- Cam intake centerline is 106°, should I advance or retard it a bit?
- On the cylinder heads, I plan to reduce the head bolt lump, de-shroud the valves, and do a light bowl blend.
- Any other tips on these heads to maximize flow around the valves at 0.300"-0.400" lift?
I know it's hard to make recommendations over the web, but this is only the second engine I've fully built, so really needing some help.
Thanks,
Ryan
Hi Guys, I'm looking for some advice with my project, in particular cam selection and static compression ratio.
It's a 72 demon, that was previously an all original restoration. It will now be a sleeper type build, used for street driving and AutoX / HPDE days.
I want to keep the engine looking like it could have come from the factory, no chrome / bling, and will have these key parts as limitations:
- Original air cleaner assembly (cutout in back for airflow)
- 360 exhaust manifolds (ported on the short turns, and polished inside)
- Stock valve covers (will spacer to clear rockers)
- Turbo style Dynomax 2.5" mufflers, dual exhaust
- 91 octane pump gas
So far, I have the following setup on the engine:
- 360 block, 0.030" over
- KB107 pistons, +0.005" deck height
- 0.032" squish, closed chamber heads
- Edelbrock heads, OOTB RPM
- RPM Air-Gap Intake
- Edelbrock 800 cfm carb
- Comp Cams 275 DEH, Hydraulic, 219/235 @ 0.050", .462"/.482" lift
(previously installed to work with exhaust manifolds)
- 1.5 roller rockers
- Static Compression ~11:1
The car has a 3000 stall converter, 3.91 gears, and will have 26" tall 245/45/17 RE-71R tires.
This engine will spend most of it's life at 3000-5000 rpm, but needs to idle when stuck in some traffic. I don't care about vacuum inches, it's manual brakes & steering.
Questions:
- With this cam / compression combo create too much cylinder pressure? (for pump gas)
- Should I change to 1.6 ratio rockers for more lift?
- Cam intake centerline is 106°, should I advance or retard it a bit?
- On the cylinder heads, I plan to reduce the head bolt lump, de-shroud the valves, and do a light bowl blend.
- Any other tips on these heads to maximize flow around the valves at 0.300"-0.400" lift?
I know it's hard to make recommendations over the web, but this is only the second engine I've fully built, so really needing some help.
Thanks,
Ryan
