Just wondering if some of you all could help me with an idea I had for my 5.3 bare block. As of no I have the block, a 5.7 crank as well as a set of 5.7 ( 241 ) heads. I was just curious if I took the block up to a 3.900 (5.7) bore size and used the 4.8 rods, they are longer than the 5.3 rods if I believe. I am not sure. Basically what I am looking to do is what those of you with a 6.0L block would do to get a quick revving, lower displacement, i.e. a 327. Would there be any benefit to doing this with a 5.3 block or should I just not even get into a short stroke, large bore? Thanks
Shane

 

Dude the 5.7 crank and the 5.3 are the same, and it definatley depends on your powers goals on what engine to use for your platform. With the block you have now, I wanna say that i think your most obtainable STABLE cubes would be 383 give or take a couple cubes. If your only going for like 600-800 hp and maybe 500-700lbs trq then stick with what you got and continue on. If the block is iron you might have luck taking it even higher than that!!

 

Sorry for the error....I meant 5.7 crank as in the corvette crank ( simply to save some reciprocating mass ) Thanks
Shane

 

makes sense

 

The reason I ask is because I am planning on installing it into my '86 Fiero GT for a real screamer. Just wondering if the combo listed above would make a big difference in the engine characteristics, such as quicker and/or higher revs. I am not trying to make 600 hp but would def like to see atleast 370 or somewhere in that neighborhood. Thanks
Shane

 

Anyone with ideas?

 

370 should be very easy with anything near that displacement, you could get that out of a 325

 

So I should take the block up to a 5.7 bore and use the 4.8 rods? Thus giving a shorter stroke yet nice displacement?

 

The rods won't change your stroke. If you use the 4.8 rods you will have to get custom pistons made which is cost prohibitive to a mild combo like that. I would go with the 3.9 bore and pick up a set of stock ls1 pistons then you would have an iron block ls1 for cheap.

 

stroke it!!! trucks like torque. longer stoke=more torque. a short stroke will rev high and make hp but without enough torque and alot of weight (i.e. a truck) it can take a while to get to the sweet spot.