LOOKING FOR ENGINE BUILDER ADVICE.

[cab0154]

with the 31s i would either put more gear in it, or put a 3 speed in it before i did anything. I would think with what you have under the hood already you should at least be able to run some mid 6s on motor

[CGT]

If you already have pistons suitable in every other way, can't you just touch up the reliefs to suit the 60/40 shifts?

You can.

Please explain. Would love to use what I have and spend money else where. Wouldnt shaving on the pistons change the balance of the rotating assembly? Need to have it rebalanced?

Cut the end off of an old valve, turn the end to a point. Bring your piston up, go through the guide of your new heads with the old valve(punch), make some marks at and around tdc. You can do some measuring from your punch mark to see any potential issues with the valve spacing. Those marks will be useful if you do end up needing to fly-cut your pistons.

[splitdecision71]

You can.

Please explain. Would love to use what I have and spend money else where. Wouldnt shaving on the pistons change the balance of the rotating assembly? Need to have it rebalanced?

Cut the end off of an old valve, turn the end to a point. Bring your piston up, go through the guide of your new heads with the old valve(punch), make some marks at and around tdc. You can do some measuring from your punch mark to see any potential issues with the valve spacing. Those marks will be useful if you do end up needing to fly-cut your pistons.

Thank you!

[splitdecision71]

with the 31s i would either put more gear in it, or put a 3 speed in it before i did anything. I would think with what you have under the hood already you should at least be able to run some mid 6s on motor

4.56s, 5000k stall, and 31 inch tire needs more gear? Im shifting at 7500 now. With weight of car we are calculating around 470hp.
Best et on motor to date was 6.83 @ 100.90 mph.

[cab0154]

to get to what a 4.10 would be with a 3 speed youll be need like a 5.60 in back with the glide. plus that thing has a tall tire. i know it isnt apples to apples, but the last low budget clevor 408 ford we did at 3k lbs on motor went 6.30s@109-111 on motor depending on the night. mid 1.3 60's. had 4.56s, a 28x10.5 and a C4 with a 5800 rpm converter. so the first gear on that thing was 4.56x2.46 = 11.2:1 and it had a 3" shorter tire. it is hard to outrun lack of gear.

[splitdecision71]

to get to what a 4.10 would be with a 3 speed youll be need like a 5.60 in back with the glide. plus that thing has a tall tire. i know it isnt apples to apples, but the last low budget clevor 408 ford we did at 3k lbs on motor went 6.30s@109-111 on motor depending on the night. mid 1.3 60's. had 4.56s, a 28x10.5 and a C4 with a 5800 rpm converter. so the first gear on that thing was 4.56x2.46 = 11.2:1 and it had a 3" shorter tire. it is hard to outrun lack of gear.

Makes a lot of sense, Thanks for the input. I will try some 28s on it and see what happens just to experiment a little.