Originally Posted by MILD THUNDER

SB, your article you posted on the other thread, got my wheels turning this morning. In that article, the purpose was a cylinder head shootout. What I couldn't help buy notice, was the overall build.

They had a ZZ502 GM crate shortblock. WIth most of those heads, the compression ration was in the 9:1 static range. Up top, sat a holley HP 1000cfm, 4150 carb. Camshaft, was a 245/250, 650 lift, 112 LSA solid roller. Not a very agressive lobe cam.

Aside from the fact, this 9:1 502, made more power than Tim's 9.5:1 540 with afr 325's and CNC chambers, I was looking more at the powerband.

Tims engines made PEAK TQ, at 4400RPM. Peak HP, at 5800RPM. From 5400RPM, to 5800RPM, tim gained, 11hp. 618 to 629.

This 502, made peak torque around 5200RPM, and peak HP, around 6200RPM. From 5400, to 5800 rpm, this engine gained 35HP.

Tim's cam is a 241/246 duration, in a 540 CI. That engine, while a solid, was 245/250 duration, in a 502CI

Anyhow, that engine in the article, seemed to make peak HP, 1000RPM over its peak torque rpm. Tims engine, making peak torque at 4400RPM, also seemed to start dying off 1000RPM over its peak torque, around 5400RPM. Do we still think smaller cams is the magic bullet in tims engine?

Originally Posted by MILD THUNDER

I entered the parameters, for 5500RPM max. I don't want to hear the backlash from the 6000RPM durations, and how someone built a 632ci with a 224/234 cam and it rev'd to 7200.

454=229/234
502=233/240
540=248/256
572=252/263
598=253/256

Originally Posted by articfriends

Baro, air temp, station press, humidity,altitude etc. To see 3% you need to have almost perfect air, ie low humidity and around 60 degrees intake air IF using j607, i cant see ypur dyno sheets on my ph but which cf was used, sae1349 yields numbers 3.9% lower than j607 . Crockett, mer, Eddie young, gellner etc all use j607, i use j607 on my dyno, a merc engine is dynoed at 1349 so if it makes 500 hp at merc and you put it on my dyno it should make 520 corrected. If your motor dynoed at 630 hp w 1349 if you put it on any dyno using j607 it would magically make 3.9% more, ie about 655hp, only useful for comparing dyno to dyno though. 99% of shops use old j607 cf because their nbers would look low in comparison to other shops if they used 1349, fwiw, Smitty

Originally Posted by I.C.U.Lookin

Was this equal power at a given rpm or to make a max hp at 5500 for each combo?

Originally Posted by getrdunn

What's your thoughts on 502? Anyone here with similar hp and tq with 502. Only good thing in comparison is if Tim wanted to remain propped at 5,500-5,600 wouldn't be much difference but I have a feeling he'd rather see his tachs at 6k and making 700.

That is a pretty tight tq to hp spand. What do you think keeps this to such a minimal spread? Many or few factors? So often I see anywhere from 1k to 2k plus with 1,300-1,500 being the norm it seems.

Good post btw. Hope Tim doesn't see it though.

Originally Posted by MILD THUNDER

I entered the parameters, for 5500RPM max. I don't want to hear the backlash from the 6000RPM durations, and how someone built a 632ci with a 224/234 cam and it rev'd to 7200.

454=229/234
502=233/240
540=243/252
572=252/263
598=253/266

Originally Posted by Full Force

My fatness

Originally Posted by MILD THUNDER

I have a camshaft design program. It seems to work very well against, what some cams/builds have seen on the dyno as far as powerband goes.

Anyone willing to guess, what change in .050 duration, there would be on a hyd roller, between a 502ci, and a 540ci, looking to make maximum power at 6000 engine speed, if all other things were equal?

Originally Posted by getrdunn

What would it look like if you added 8% to duration and lift to cam used in z engine. That's plus or minus percentage difference in CI from 502-540. Just a thought. 264/270-702/702.

Originally Posted by SB

That effects form factor,not correction factor.