Don Terrill’s Speed-Talk

That block will usually take a .060 without concern; scuffing could be a fitment issue, overheating or both. If you find other indicators on the teardown, have it sonic checked. I have also seen defective egr valves cause scuffing, might question the owner about drivability issues. Agree with the pr...

Watching with interest. I worked with those heads many years ago on a circle track deal; there are three sets of ported castings on the shelf. Looking forward to seeing how my home worked castings compare to the pro's.

I don't know why USRA even posts engine rules; the only time I've seen a dq was for body and or suspension infractions. Most of the midwest racers know what they can get by with (and at what track) so will run an outlaw carb where they can and a gauge legal where they need to. One of the engine buil...

On the blocks with o-ringed p/v I've seen one case where the o-ring was rolled (on installation I suppose) causing the pv to leak. I use a little light lube on the o-ring when installing the p/v in blocks that use an o-ring; Do not be tempted to use a regular gasket on an o-ring style block.

4412 carb rule? The 2701 is better if so; it is still a turd manifold but it is the "best" of the turds most of the rule makers dictate.

Rick Schnell (?) filled his blocks with aluminum but with a bore that's + .250 there is going to be some movement. Having never done it I "suspect" there would have to be a pre & post heat involved moving things even more. Epoxy might be the best alternative but getting everything clea...

SP70, found my notes on the 6 cylinder 4412; Hsab=.031, Iab-.073, Ifr=.028, Pvr=.043, e-bleeds& kill bleed =.028, main jet=#73. The .035/.069 combo "might" have been the root cause of some of the problems, if the air bleeds are replaceable scare up some to take to the track with you (o...

40 grit finish killed the burr gains

As Tom pointed out: A 6 cylinder is @120 so in general can use more cfm than expected. That 500-cfm rating is at 3 inches not 1.5 so don't be tempted to use a 7448. Bench set your float by inverting the fuel bowl so the float is resting on the n/s and adjust until a 13/32 drill shank will slide betw...

I have not found my 6 cylinder specific specs so this is from memory (many years back): As Tuner said, throttle shafts parallel to crank centerline. Carb mounted with fuel bowl toward left front. I try to use early fuel bowls with the ball check rather than the rubber diaphragm on acc. pump circuit,...

The XP 4412 is not recognized as a legal carb in some sanctioning bodies. I believe USRA and IMCA have specific wording preventing its use. If you do decide to keep the p/v the restrictors behind the valve will need to be reduced; seems like I ended up with either a blue or orange cam on the 250. I ...

If the information is out there it is scattered all over hells half acre; the book puts it in your hand. 70 dyno pulls, manifold and carb changes; makes my back hurt thinking about it. I don't know Eric, but I do appreciate hard work so I purchased the book (even though I'm semi-retired). Well deser...

Doesn't the Ultra have the adjustable idle bleed set up under the carb stud? There is a relatively heavy spring in that arrangement.

Evidently there is now an 89 throttle body manifold and various adaptors now in the mix; one of which adapts the holley 500 and one to adapt a stromberg that is similar to the large base bbd. By stacking adaptors they can also mount the smaller bbd to the manifold. If I was the guy that had all of t...

Might check with Dan @ Cavco Equipment; he had one listed a few weeks ago...