sup guys. just curious...will ls1 heads fit on the 5.3 v8 and the 4.8 v8's? and also if i'm looking up cams..do i have to specifically look it up for the 5.3 and 4.8's..or do cams that work for ls1's work in the truck motors as well?

 

the LS1 engine is a gen III small block. the LR4 and LM7 are also. the parts for it interchange just like the did on the gen I small block. the LS1 heads will fit on the smaller bore LR4 and LM7, but the compression will take a hit since the chamber for the LS1 head is larger. there isn't much of a good reason to switch to heads from the 5.7.

 

i figured since they more then likely outflow the lm7 heads n such it'd be a good reason to do it.i have no clue how well the stock heads on the trucks flow either.

 

the stock 4.8/5.3 heads do pretty well in stock form. the main difference as far as flow goes between them and the 5.7 head is in the intake valve sizing. the 5.7 has a larger intake valve.