Im rebuilding my motor after a #7 piston bad ringland.Im between doing a forged 347 stock block are a 370 iron block. I know i will pick up about 25 horses on the 370 but i will also gain 80lbs.Which would be better 80lbs lighter 347 or 80lbs more 6.0 with 25 horses? i will be spraying about 150-200 nos on a 240/244 cam full bolt ons.This will be a 90% track car very little street so driveabilty not a big concern.

 

The 370 will open up your head choices, but if its a nitrous motor, id just spay more on the AL block to make up for it. Im not really a fan of adding weight on one of the worst possible places (the front) of a car

 

Well from my personal experience, I chose a 370 for added cubes on budget but say little improvement over a 346 in times at the track. The added weight increased my 60', my times were about the same .2>.3 improvement but trap speed was improved by 5mph/

That is why I'm switching from H/C to FI to make better use of that added weight in a more civilized manner.

If I had to do it all over again I would stay AL 347, basically what I'm saying if going iron, go bigger cubes, at least 408

 

 

how much spray will the al347 handle, once i get cage wheels all etc i will be going al427 l92 motor with the intake from 347 with larger heads.

 

Forged, ~300 shot

 

i would say its very much a personal choice, theres pro's and con's for both, myself went with the 370 being on a budget and wanted the 4 inch bore.

But then again i have a ls1 in a 3rd gen and i've already lost so much weight from the nose that my coil overs adjusted all the way down still sit about 1/2 inch over stock haha, so maybe now i'll be at stock ride height with the iron back in .