2270 Engine Questions, Crank and Rods Options

[yeahmag]

I'm getting close to having all the parts for the 2270 build, but have a few questions:

• Crank brand: DPR, Scat, or AA? AA and Scat are new forgings but cost a bit more than the DPR crank. DPR is well respected in these parts.
• Crank size: Seem like a shame to leave it at a 2270 (78mm) when I could go up to a 2316 (80mm). Chevy journals.
• Rod length and type: Planning on 5.325" and Chevy journals for both clearance and the better bearing availability. Can I go longer for a better rod angle?
• Rod brand: Anyone have a preference? They all seem to be in the $400 range these days.

This will be primarily an autocross engine with some weekend drives. I also drive to events. The engine needs to be able to spin to at least 7500RPM even if it's not making power up there.

Here's the rest of the config (all of these parts are in hand):

• JE 96mm pistons with AA barrels
• Type 4 Store 9550 cam (86b/86c variant)
• Set of beautiful Finch heads I scored from Len Hoffman years ago
• Tangerine Racing 1.75" header
• 48 Dellorto Carbs with a 38mm vent (probably need to go to a 40mm vent)
• Dry sumped (either CB or ideally TP)

[cgnj]

Just had a conversation last Friday with Jorge @EMS regarding a long stroke long rodded motor. My concerns were engine width and cam clearance. I built a 2270 in the stone age and went thru the knothole to get it right. I just sourced a W code case and wanted to build the biggest motor I could and still do a valve adjustment without dropping the motor.

My take away is over 82mm stroke=Chinese crank. No thank You.

No case clearing required with 2.0 journals. No rod cap clearing for cam. (I find this hard to believe but I'm going to go with it).

You have your heads and cam in hand. Confirm the chamber volumes first. This was the biggest problem with my build. They went to Headflow Masters with 60 cc volumes and came back with 54 cc volumes. They work fine it just made the process take much longer.

Is the cam on a reduced base circle? I used a 163/86b on reduced base circle. With VW journals I had to clear the endcaps.

I switched to the newer German swivel foot adjusters. Much easier to check the valve lash.

I think you're good @ 80mm with 5.5 rods. I think end cap to cam will be your biggest obstacle.