L31 Extreme Budget Build

[Orpedcrow]

LT1s are flat top giving you more compression. In an earlier post @L31MaxExpress figured ~10.3:1 compression

Oh, nice! That’s what I figured the difference was. Thanks

 

[letitsnow]

Is that comp too high for pump gas? I was always told not to go over 9.5:1, but that was with a stock cam.

 

[L31MaxExpress]

Real cool build, whats different about the lt1 pistons vs l31?

Lighter weight rotating assembly and more compression. The Mahle LT1 flat tops are also more consistent in weight.

 

[L31MaxExpress]

Is that comp too high for pump gas? I was always told not to go over 9.5:1, but that was with a stock cam.

My 383 in the Express is 11:1.

 

[Hipster]

Lighter weight rotating assembly and more compression. The Mahle LT1 flat tops are also more consistent in weight.

Curious as to how the lt pistons compare in weight to the 305 pistons for crank balance/bobweight?

 

[L31MaxExpress]

Curious as to how the lt pistons compare in weight to the 305 pistons for crank balance/bobweight?

Believe it or not the LT1 pistons are all between the lightest and heaviest L30 pistons. 3-4 grams difference in the L30 pistons. The LT1 pistons were 1-2 grams difference. The LT1 pistons were about 1 gram heavier than 5 of the L30 pistons and 2-3 grams lighter than the other 3.

 

[Hipster]

Thanks. I have a 305 Vortec Mercruiser the PO didn't winterize properly and broke the block as well. I was always under the impression a 305 crank/350 pistons was a no go.

 

[L31MaxExpress]

Thanks. I have a 305 Vortec Mercruiser the PO didn't winterize properly and broke the block as well. I was always under the impression a 305 crank/350 pistons was a no go.

The lightweight 350 pistons are a different story though. Using the 305 crank with the lightweight 350 pistons is actually even suggested in the LT1 rebuilders guide.

Rebuilding the Chevrolet LT1 Engine

Although it shared many common dimensions, looked much the same and even had a few common parts, it was totally redesigned to provide more power with lower emissions and better fuel economy.Click Here to Read MoreAdvertisement Compared to the 1991 Chevy 350 L98 with TPI, the LT1 made 20% more...

www.enginebuildermag.com

 

[L31MaxExpress]

Also, have you seen if you can get heat shields for them or if stock ones work?

going to be a PITA to get a spark plug socket on the plugs, but the stock vortec heatshields did fit on the passenger side. About to put the driverside together. I did some digging, so far have only found a pair of RH shields. They usually hit the scrap pile with the OEM manifolds or go back on the stock engines I put in.. I had to tweak the tabs a bit to get the bolts through them and they actually touch the manifolds, so not sure how useful they will be.

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[Orpedcrow]

Those manifolds look nice! but I’d rather replace melted plug wires than deal with those daggum heat shields