Don Terrill’s Speed-Talk

DrillDawg wrote: ↑Mon May 07, 2018 12:41 pm I would like to see the uncorrected numbers.

Looks like correction around 1.10. If that helps you out.

, I thought it would be at a higher altitude, thanks.

It will be going there but all dynoing in south where air is more readily available!Any specific reason?

Mostly my interest, if you have a 10% correction at 700' that means it made around 700 uncorrected and it might be less where you are. So a 2x4 header might be a little much is what went threw my head.

Yes makes sense. The headers are a set i bought for dyno purposes. Will not fit any of our chassis. As a3 has its own bolt pattern.

The 4x3 collector extension should increase the velocity and decrease the pressure at the 3" which will be sucking on the 4" to help keep the velocity up which decreases the pressure in the 4" . Might not work In your case, but something to think about. You can see if the exhaust side is doing it's job by looking to see if there is any reversion in the intake system or a "wet" exhaust port.

Steve.k wrote: ↑Sat May 05, 2018 10:41 pm 14:1 racetecs
4.155 x4
Dual 1050 sheet metal intake
Camresearch cam .780 lift
266-272@.050 on 112
A3 nascar heads with narrowed c3 style ports 377@.800 and 256@800
Kevko bulged pan.
2" x 4 inch collector.

Something's wrong.
We were making over 800hp with 420ci SBF dirt latemodel engines in the 90's, with similar durations, but less lift.

The heads don't work as well as the flow numbers would lead you to believe.

Just remember boys we didn't finish session with ign timing at 30* and carbs still fat. So we not at end of rope yet. A trusted source just dynoed a set of these and ign timing peaked at 36. For every 2* we added we were gaining 10hp.

Total timing depends on a whole lot of things, and it could/will vary from engine to engine depending on compression, piston shape, chamber shape, etc.

An easy thing to do at this point would be to pull a plug and see if it's close on timing or not.

I hope you're right though, but I agree with Mike....

Mike said something wrong but he didn't know the full story im thinking. I would imagine lots of guys made more hp on less cube to but they were likely spinning 8500 and cams cut in 106 or 108 centerlines im thinking. Who knows. After we rerun this week and get north of 7000 we will see.

It's not really making more with less cube, it's comparable displacement combinations making more horsepower with less camshaft, less compression, less carburetor, etc.

I'll keep my toes crossed for you.

Well know doubt there's combos out there making more power with parts available today. I would like to see a combo with the same heads(A3)less carb and camshaft and on gas. No vac pump and no dry sump oiling! It's possible overlooked something. I know one a3 motor thats close but sings quite abit higher in the rpm notes. So really tough to compare.

My 354C was pushing 1.75 hp/ci with factory 4V heads, unported, 12:1 compression. Turning a bit more rpms than you (7900-8000), but not bad for 300 cfm pieces.

Very impressive but totally different build.