Don Terrill’s Speed-Talk

Have done a went a couple different ways for my NA engines I builds for pulling. The first I did was a heart shaped combustion plate between the block and head. The rest were a dished piston with valve reliefs.

Scott

Ran them in a high compression 17-17.5:1, all iron(block and head no water), alcohol, NA, MFI, pulling I6 based on what NGK recommended for this application. Seemed to work ok, this was a while ago but as I recall they were expensive plugs.

I have a 331 with AFR 205's with simular duration on a SR but 110LSA, .664in /.633ex lift, it loves the super victor, In fact when replaced with a performance products version of the victor Jr the low end driveablity improved. I do run a manual with 4.56 with simular weight turning to 8K.
Scott

10 years with SBF 331cid +.650" lift, 250ish @ .50 duration. Like said no bypass oil filter, it gets reved upon start up until up to temp. It's down right now as I had a rattle in the lower end, apparently a cracked Eagle crank, excessive cam end play which went together that way. 6-8K miles, 1...

No but I just did a tractor engine with a mirrored chamber 9:1 comp, .6" lift cam, with a stock carb it is 30% more hp and just sips the fuel on 87 octane. I am intrigued by the symmetric dish.
Scott

Can't comment on Pipemax. But I am familiar with that head and you are on the right track with valve size. That port in a filled water jacket configuration can flow easily 370cfm. My only comment is it needs more stroke...just under 5". Oil galleys may need to be relocated

This was copied off a NASCAR rocker for our tractor program. To keep things simple out of 8620 steel. We were .860 lift with no issues with longevity.

I assume your talking at the crank hp? Put a solid roller with another .1 lift, a super victor intake and have pro systems or a carb builder of your choice build you a 780cfm carb I bet you would pick up 100. I'm making 470rwhp out of my 331, 10.2:1 with AFR 205's, do the math that is well over 500 ...

I wanted to share my results of the split manifold test I performed. It was unsuccessful. The first attempts were to small at 1 1/8" &1 1/4", based on sound and area calculations to the 2-1/16" single. So I tried 1-1/2" 1-3/4" and just let them terminate wherever. Could ...

This may be application specific, but the best header commercially sold for my Jeep 4.0 is the arh 6:1. Here’s a pic of mine. It also uses the rotational firing mentioned by others. https://i.imgur.com/zPKcMUn.jpg The next best header is a 6:2:1 design and doesn’t make near the power the arh does. ...

How about a vertical exhaust? This was me and my dads former pulling tractor. This was a Burns Stainless 6x1 1-5/8" dia primary tubes, the primary configuration followed the firing order in a circular pattern.

Update on the exhaust turning. It didn't like the small one at all down 10hp. The largest one I built was only down about 2-3hp, but looking for gains. I'm going to try the larger pipes which I don't have collects for ranging from 1-1/2 to 2".

Some videos:
A walk around after start up:
[https://youtu.be/gIsZpQWs_ao
]

Dyno pull at full load, 1800 rpm
https://youtu.be/VbhPrj3Si5g

Thanks Harry! I go back and fourth if the pipes are to small. The one is 1-1/8 od 12-14" in length that step into a 1.5" collector. The other 3 are 1-1/4 od 12-14" in length that step into a 1.5 or 1.75" collector. My carb is only 1-1/8 and red line rpm is 1800. So we will see I ...

So a update engine is built and broke in, it made 90pto hp @1800rpm, factory was 75pto hp with a larger carb at 2300rpm. I have my manifold design to try next here are my prototypes to try. The temperatures are from the dyno at full load on a cool day, it was 48 degrees F air temperature.