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use a cam out of 4.2 in 4.0

Posted: February 10th, 2012, 10:26 am
by jenmes70
if i use the the crank and rods out of a 1981 j10 in my 1996 grand why not the camshaft. it is my understanding that some stroker builders are basicaly useing that cam any way . im looking to do the poorest man stroker.i have a good 4.2 85 thousand miles on it and a used 4.0 with 109 miles want to strok it cheap with the old parts. not looking to race just a daily driver. just thought i read that and cant find it any more strker over load :banana:

Re: use a cam out of 4.2 in 4.0

Posted: February 10th, 2012, 7:42 pm
by IH 392
You can use the cam out of the 4.0, the cam out of the 258, if it's the stock one?, is a poor "smog" grind that's little more than a tent stake.

Re: use a cam out of 4.2 in 4.0

Posted: February 10th, 2012, 11:04 pm
by Retlaw01XJ
jenmes70 wrote:a used 4.0 with 109 miles want to stroke it cheap with the old parts. not looking to race just a daily driver. just thought i read that and cant find it any more stroker over load :banana:

Start with checking your lifters.... they must be matched to the cam lobe they came off of. If they are mixed up, buy new lifters. About $5 each.
If they are worn.... check with a straight edge... concave (gap in the center) means they need to be replaced. Convex (high in the center) they can be reused.
new stock (later)Cam + lifters = $180.

4.2 rods = stock pistons with a higher compression ratio. Unless you have them dished. $$.
4.0 rods = forged pistons for more $$.
Either option may require the block deck to be cut and more $$.

Plan ahead for EVERYTHING if a low-budget build is your goal.

Re: use a cam out of 4.2 in 4.0

Posted: February 11th, 2012, 11:49 am
by jenmes70
so is the 4.2 camshaft a better cam? than the 4.0 ? :huh:

Re: use a cam out of 4.2 in 4.0

Posted: February 11th, 2012, 7:33 pm
by IH 392
Guess that you were unable to interpret my previous statement?, NO, your 258 cam has nowhere near the performance potential of your 4.0 cam.