HarleyTechTalk

3 13/16" x 5 1/4" with a 7.440" rod on a stock deck case

I think that's pro gas?

I consider it a budget build, because I figure this engine would be ready to blow apart at any moment. And I figure its a throw away engine when it does. But maybe that's racing.

I got a Leineweber E-9 on hand and the largest Super D carb 2.150" venturi

The heads I would use are stock sized ports and valves, I'm not sure I'd get into the expense  of aftermarket heads because I suspect the cams gonna wreck them

Also might be interested in running an open belt for the first time

Not sure on a chassis

How much power is to be expected out of something like this? Enough power to do 140 in the quarter? Low 9's?

Big bore, big stroke & big carb with stock heads is not going to get you in the 9's.

I worked with a customer to do something similar a long time ago. We used S&S SA heads and I can't remember where the cylinders came from. We used the typical head bolts and studs through the cylinders like the Evo, but also added some more head bolts that came up through holes in the cylinder like a Shovelhead. Otherwise the head gaskets wouldn't survive. I think the valves were something like 2.200" intake and 1.750" exhaust.

My cylinders fire ring Axtell, no head gasket, o ring and interference fit on fire ring to head.

Not sure how large of valves can be put in an OEM casting, and still be able to run that E9 cam, with enough valve spacing

This sounds like an AHDRA pro gas or pro mod recipe. The characteristics of which are widely known. Chassis and clutch are critical for this to approach the low 9s in the quarter.

Characteristics Widely known?

At the track I assume. 
I know the 114ci and might have seen a 120 at a swap meet at the nitro guys space. 

I haven't spend time at the track but have been around the 3 13/16" big bore engines (not big compared to todays offerings, but on stock dimension Evo or Shovel cases it was). 

Any good links to where I can read about this 120ci engine recipe? 

Quote from: 98s1lightning on November 25, 2023, 01:47:16 PMCharacteristics Widely known?

At the track I assume.
I know the 114ci and might have seen a 120 at a swap meet at the nitro guys space.

I haven't spend time at the track but have been around the 3 13/16" big bore engines (not big compared to todays offerings, but on stock dimension Evo or Shovel cases it was).

Any good links to where I can read about this 120ci engine recipe?

Funny.

Quote from: wfolarry on November 25, 2023, 04:55:04 AMBig bore, big stroke & big carb with stock heads is not going to get you in the 9's.

Heads will get you there before just big bore , my 76CI gets me in mid 10s with great heads

Quote from: hbkeith on November 28, 2023, 02:45:46 AM

Quote from: wfolarry on November 25, 2023, 04:55:04 AMBig bore, big stroke & big carb with stock heads is not going to get you in the 9's

W   Heads will get you there before just big bore , my 76CI gets me in mid 10s with great heads
V

What heads you running ? 

Quote from: hbkeith on November 28, 2023, 02:45:46 AM

Quote from: wfolarry on November 25, 2023, 04:55:04 AMBig bore, big stroke & big carb with stock heads is not going to get you in the 9's.

Heads will get you there before just big bore , my 76CI gets me in mid 10s with great heads

Not in a big twin it won't.