Don Terrill’s Speed-Talk

It reduces bearing speed and it reduces the Bob weight quite a bit. If you consider it, the big end of the rod can be smaller, therefore lighter. The bearing is now smaller, and lighter. The rod pin is now smaller...and lighter. That means rather than Swiss cheese the counterweights you can reduce t...

I do two tests that are quite simple. first some plasticine in the piston reliefs, o ring over valve stems to hold in place, final fit second hand gasket thickness gasket on, head on, couple of bolts, then push the valves into the plasticine @tdc then pull back up and hold with o ring, head off the...

The only way to know exactly what the P/V is requires the valve springs to be used. To me, that means you need to use clay. Checking springs will always show LESS P/V than a valve spring will. I’ve seen guys notch the valve pockets because they used checking springs and when I assembled it I measure...

Pardon my ignorance, please, if you would. I had another chance to road test my Fiat Twincam today - the last nice day of the season possibly. The engine runs great but a bit rich at low speed/throttle. Here are my questions: 1. Is the plug appearance representative of the last 30 min or the last 3...

I’m not sure what eliminating the power valves in the primaries is going to do, but make it pig rich at a cruise. I would eliminate the PV in the secondaries, fix the cruise jetting on the primaries and then get WOT correct with the primary PVCR and secondary main jets. I can’t think of a single rea...

That chamber shape was ordinary in the era of lbs/cu in Pro Stock. In fact it was essential to getting high compression ratios in small displacement engines. i had Glidden's small block ProStock Chrysler engine in my Shop many years ago :) Cylinder Heads on my Flowbench ... i thought i posted Head ...

I would be interested in what Cam King thinks about how the .200 duration, effects engine performance and if what I suggested, might have any relevance: Thinking of it logically, I would think you would get higher hp, with longer .200 duration and higher lift and a wider torque band with less overl...

I was stating that my 6.5 pv’s do not pass fuel at my idle vacuum. I understand now that pv circuit is with the boosters and not the t slot. Cruise vac is 14” and I want to try 8.5’s to cover a slight hiccup at full throttle jab in high gear. I figure it needs more fuel quicker. T ram set up with t...

Do not set power valve opening from idle vacuum. Set it off of cruise vacuum and be two or three numbers lower than cruise vacuum.

Do the main jets flow fuel at idle? Neither will the power valve. Setting the power valve opening (timing) the Holley way is just wrong.

Just throwing out some thoughts/questions for discussion. I have a 9.5:1 big block chevy, aluminum heads. It has a Jones HR cam, 110 separation, .600 lift, 240-ish duration at 0.050 makes about 160 psi cranking pressure. The engine runs magnificently, pulling hard from down low to well north of 600...

I get way more pump lever movement with the pink cams vs the blue it seems. I will get a little more time with it today, just trying to figure t-slot jet sizing thinking maybe this is the culprit. I currently have an .081 t-slot jet and thinking maybe it needs to be larger or smaller, but not sure ...

Power valves open too late. You are probably too big on the idle feed restriction. If you don’t have T slot restricters install them. That .028 MAB seems awful small.

This is not true... If you primarily street drive your car VS drag race it you are better off with plenum heat in the long run. Can' determine if you are wasting your time. Seems you suspect that. Been doing it since 1980, and not one time have I had to fatten up the idle with a cold air intake. In...

The best you are going to do on a low rise single plane for low rpm is to re enable the plenum HEAT. (restrict 1 or both sides to about a 3/8" hole. ) The cold manifold is killing you on the street.. Thats why you hate the carb. Then install a plenum divider. This also makes a big difference V...

EDC and a couple others nailed it. He has WAY TOO MUCH clutch. That’s always what that is. Don’t use a steel flywheel. You don’t need the hit with all that gear. It certainly is NOT a carb issue. It’s a clutch issue. Until the guy gets that, he’s going to fight the car. Take clutch out of it.