I have pics of them side by side an the 862 ports are a good bit larger. I can't get the pics to post up. heres the specs ported 5.3 heads PRC 660lift springs, ferrea 2.02 intake and 1.57 exh valves, titanium retainers, multi angle valve job.. milled .030/ now have a 58cc combustion chanber. Guess this woulda been smart to have at the start lol.

 

IF the 862 ports are larger, they have been ported or someone attempted to port them. You can hurt flow very easily as material has to be removed in the right areas and if the port volume is too big then the velocity will be poor.

The best thing you could do would be sell them, and buy some 243's to be honest.

 

Yes that would have been smart.. Your compression is going to be in the 12 range. I hope your running 93. You should pick up alot. If it stays together

Anyway keep us updated.

 

What could they hurt ? I always run 93.

 

If they were cnc ported or hand ported by a reputable shop that's fine. If they were garage ported with a dremel and a 30 pack, that could be bad.....lol

 

Id be worried about summer heat and that high *** compression ratio in a heavy truck.

 

Its a rcsb. Whys the compression bad with heat? Didn't kno there would be all these issues.

 

Some good reading


Engine Compression Ratio - Tech - Popular Hot Rodding Magazine

 

So ima need a lower temp thermostat. I'm not trying to kill my motor.

 

Are these heads going to hurt my stock motor? I assumed they were bumping my compression to 11-11.5.