I agree with madkaw.....higher lift cam with more duration. You can pretty much go with a higher CR with the P79 head, however, you are pretty well locked in with your build. I love my Isky Stage III cams (.490 lift) no clearance problems. Sounds like a nice build.  Good Luck

Guy, Do you shim the springs too...outer and inner?

Edited August 7, 20186 yr by jonathanrussell

24 minutes ago, jonathanrussell said:

Guy, Do you shim the springs too...outer and inner?

I think you have to 

Yes I have accounted for shimming the springs. Have additional outside washers.

I'm surprised to hear that you recommend more duration.  I admit the lift is mild at only .480" but the duration of 254@.05" is a lot comprared to other grinds.

Diseazd, what duration is your isky cam? Also, what are the specs for your build?

Do you think with a home port I can improve the head enough to utilize more than .480" lift?

Edited August 7, 20186 yr by jy.s30z

1 hour ago, Diseazd said:

No Site, because the springs are shimmed up and the valve is .080 longer. He can go stock valve seals. BTW jy.s30z.....don’t forget the spring shims....don’t see them mentioned.

Yes jonathanrussell....outer springs are shimmed .080 to make geometry correct.

Edited August 7, 20186 yr by Diseazd

32 minutes ago, jy.s30z said:

Yes I have accounted for shimming the springs. Have additional outside washers.

I'm surprised to hear that you recommend more duration.  I admit the lift is mild at only .480" but the duration of 254@.05" is a lot comprared to other grinds.

Diseazd, what duration is your isky cam? Also, what are the specs for your build?

Do you think with a home port I can improve the head enough to utilize more than .480" lift?

 

32 minutes ago, jy.s30z said:

Yes I have accounted for shimming the springs. Have additional outside washers.

I'm surprised to hear that you recommend more duration.  I admit the lift is mild at only .480" but the duration of 254@.05" is a lot comprared to other grinds.

Diseazd, what duration is your isky cam? Also, what are the specs for your build?

Do you think with a home port I can improve the head enough to utilize more than .480" lift?

My Isky Stage III is 290 degrees duration. I’ve built 6 of the .080 shaved P79 head/ F54 block different  variations. All 6 have Isky Stage III Cams. Four have .040 over flat top stock pistons. Two have Datsun Spirit Forged Pistons (they are 3.1 Stroker Motors). I built two with L24 cranks with L28 pistons and rods, two with L28 stock cranks with L28 pistons and rods and two with LD 28 Stroker cranks and forged Pistons and rods (Datsun Spirit built the two 3.1strokers). I love each and everyone of them......the strokers the most?.  I would definitely go with the Isky Stage III....do it now or you will regret it IMO. I have several build threads under (topics) on my home page you can reference. No ping at any rpm or load on any of the six engines.....fabulous set up you are building.....kudos. Let me know if I can help.

Guy

Edited August 7, 20186 yr by Diseazd

Guy,

Have you run any of your engines on a dyno? 

9 minutes ago, Diseazd said:

 

My Isky Stage III is 290 degrees duration. I’ve built 6 of the .080 shaved P79 head/ F54 block different  variations. All 6 have Isky Stage III Cams. Four have .040 over flat top stock pistons. Two have Datsun Spirit Forged Pistons (they are Stroker Motors). I built two with L24 cranks with L28 pistons and rods, two with L28 stock cranks with L28 pistons and rods and two with LD 28 Stroker cranks and forged Pistons and rods (Datsun Spirit built the two strokers). I love each and everyone of them......the strokers the most?. I would definitely go with the Isky Stage III....do it now or you will regret it IMO. I have several build threads under (topics) on my home page you can reference. No ping at any rpm or load on any of the six engines.....fabulous set up you are building.....kudos. Let me know if I can help.

Guy

Thank you very much for the help and encouraging words on my build. 

I just looked up the ISKY cam and it is 290 adv. duration and 242@.05".  From my understanding, advertised is taken at 0.006" most of the time.  So for my cam, the advertised would be 311 duration and 254@.05". So, my cam is bigger than the ISKY with slightly less lift at only .480 vs .490.

I'm going to search through ur builds for reference.

29 minutes ago, jonathanrussell said:

Guy,

Have you run any of your engines on a dyno? 

Yes Jonathan....The L28 crank motor is 170 hp at the wheels, so approximately 200 at the flywheel. Eiji said the Stroker motor should push 250 at the flywheel, but I haven’t dynoed one yet.

3" exhaust seems excessive. A turbo build might be different, but on an NA motor larger exhaust isn't always better

Just now, Patcon said:

3" exhaust seems excessive. A turbo build might be different, but on an NA motor larger exhaust isn't always better

Thanks for the input.  I'm contemplating, ditching the 2-1 part of my header and running two 2-1/4" or two 2-1/8" pipes.   

Anyone else agree that 3" is excessive for my build?

6 minutes ago, jy.s30z said:

Thanks for the input.  I'm contemplating, ditching the 2-1 part of my header and running two 2-1/4" or two 2-1/8" pipes.   

Anyone else agree that 3" is excessive for my build?

Two 2 - 1/4" pipes (7.96 squ in) is even larger than a single 3" (7.08 squ in). Even the two 2 -1/8" (7.10 squ in) is even larger.

I found this on another forum:

"As an owner of a 3.2L Rebello engine I would recommend what Dave uses on his dyno (and what I have on my 240), a Sebring Tuning muffler and either a 2.5 or 3-inch custom bent exhaust pipe."
 

That's a 3.2L. A good bit bigger than what you're building and a $3000+ Rebello head that breathes really well. BTW those kind of heads are really not a do it yourself kind of thing...