[Healeys] Compression ratio for a fast road 100

[Hap Polk]

Patrick, Perry, Michael,

If my memory serves me correct the fast 100s race guys in 1960 Southern
California were saying that they were reaching 8000 rpm. That was with
using:

Line bored main bearing saddles.

Fully polished crankshafts.

Fifteen pound flywheels.

Some, I believe had front crank dampers, but not all.

Lightened rods with high strength rod bolts.

Flat top pistons.

300 degree cams, Isky or Elgin, when combined with the flat top pistons gave
reasonable dynamic compression.

10 to 20 thousands milling on the head.

"Open it all the way out" porting on the head, with manifold matching.

1949 Buick Road Master straight 8 lifters and push rods.

Polished valve rockers.

Titanium valve retainers, I think made for 265/283 Chevys.

I think 265/283 Chevy valve springs, often with larger diameter fly cut
valve spring head surfaces.

Exhaust headers with exhaust before the rear wheel.

Rich SU needles.

I think most had the vacuum advance defeated.

 

Michael, I take your point based on your experience. If these guys were
reaching 8000, the question remains was there enough torque above 6000 to
make it worthwhile?

 

As I said before, in 1960 I installed the Road Master lifters and pushrods.
They were both lighter and stronger than the Austin items. I often explored
5000 - 5200 rpm. I felt the engine was smoother with the lighter valve gear.

Hap Polk