08 silverado z28

I got a 2006 single cab hemi with the 5.7 and the automatic. I was wondering if I found a 6.1 would it bolt up to my transmission? I'm new to all this hemi stuff so if anyone could help me out id appreciate it. And if anyone has some insight on what people are doin to beef up the tranny. Already had it rebuilt once. Would the transmission from a 6.1 work in a truck? Please help lol

FrostKing

Yes, the exterior of the 5.7 / 6.1 blocks are identical. A transmission from an SRT car would bolt to the engine, but a standalone controller would be needed to run it. The transmission I have is a stage IV 545RFE from Sharadon Performance which has the usual valvebody & case mods to increase hydraulic flow for faster/harder shifts and also modified to allow Red Alto / Kolene steels and much more of them. The hard parts in the stock transmission are extremely durable with only the converter and clutches really needing improvement.

Your 5.7 can also be stroked to 6.1 or 6.4 very easily.

HemiLonestar

What block would hold up better, especially still being used a truck engine, the 5.7 or 6.1?

FrostKing

Both the same. The blocks are nearly identical with the 6.1 having a revised windage tray and openings in the bottom webbing to accommodate higher RPMS plus they have piston oil squirters.

HemiLonestar

By all the research I've done, plus looking at the engine itself, it seems the 6.1 casting has a more reinforced bottom end. Plus I've never heard of anyone blowing one up below double digit boost numbers, whereas every used STS kit (and similar items) I've (just me personally) seen for sale come from a vehicle with a 5.7 that got the boost turned up too high and boom. I've been looking for a 6.1 to build on as it seems like an all around better engine to start with.