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)

[JamesM]

I know some people have trashed on AA pistons in the past, but i have their cast pistons and rods in my 2056 autocross motor and have had zero issues so far and I have datalogs running it up past 7k RPM.


Only mentioned it because it seems to me like just going with their 96x78 engine kit just seems like the easy button, though maybe go with the JE piston upgrade if you are planning to really thrash it.

New forged crank vs something welded and cut down. I have heard DPR is great but i have also heard of a couple of their stroker cranks breaking. Supposedly the AA 96x78 kit can be dropped in with no machining of the case as well.


Why were you looking to have additional rod options?