Don Terrill’s Speed-Talk

I figure that the best compromise, would be a 224° @ .050 SR cam lobe for what you want. The longest .020 duration lobe I could find for that .050 dur was 262°, in a SR. With a 115 ICL, you could do it with the 72cc head but,you'd have to run ~.025 deck clearance on the piston to get by with 92 oct ...

It's not the overlap that bleeds off compression, it's the IVC position. The later it closes, the less air is trapped.

I would change out the solid roller. A new cam will be +/- $650. For about 1/2 that cost, you can go to a HFT cam and lifters.

For your purpose, you don't need the ramps or lift that the roller can give.

Tuner, I'm interested in how you got this slope, "20 at 2000 with a slope to 26 at 6000".

What kind of springs did you use for that or what tricks were involved?

I gotta ask, why not a 351 based SBF?

Either a Bill Elliott inspired C or a W.

On a similar cam (270 @ .050) but, 1.76 RR (.710 valve lift), Bullet recommended 220/230 seat pressure and 575/620 open.

WRM's 1343 PAC's fit that bill.

Check out the different bearing suppliers for the thickness of the bearing shells. Find a shell that is .0005 thinner that your Clevite's and get a 1/2 set. Replace one side on the rods that you want to open up.

Straight from the horses mouth.

The factory spec for the crankshaft pilot diameter is 2.499/2.500, add what ever clearance you want to it.

If you catalog them and list them on this site and others, I'm sure you could get rid of them and maybe make a buck or two.

I'd be interested in any piston catalogs.

To improve flow, the chamber should be re-designed so that instead of two tight 90 degrees turns the gas mix would do one not-so-tight 180 degrees turn.

Wouldn't it be difficult, if not impossible to have any compression, with a layout like that?

That's why I suggested going to a hyd roller. You can get nearly the same adver & .050 timing with those. For example you can have a Howards lobe that is:

268/215, .313 or .333 lobe lift or a 282/229 and 6 different lobe lifts from .300 to .374

Added:
278/225, with 5 lobe lifts from .300 to .350

You'll have a hard time finding a solid roller to fit your needs. Most off the shelf SR are for race engines. You could do a SR custom cam though. Howards has lobes that will do it.

I would suggest a hyd roller, there are lots of those in the duration and lift that you will want.

If you move it from 111 ICL to 108 ICL, your advancing it 3°, 2° advanced from straight up. Doing that should lower your peak rpm a little but, increase your mid range a little and maybe your average hp, in the rpm range you use. Adding 20° to your duration, will raise your peak rpm by about 500 rpm...

mag2555 wrote: ↑Fri Mar 15, 2024 6:36 am If I recall right off the top of my head the valve angle is like 14 or 15 degrees if that’s what you need.

The valve angle is 13°. Seems Ford was way ahead of it's time when you look at how all the after mkt mfg has dropped their valve angle.