[454C10]

check out this dyno list.

http://www.ryanscarpage.50megs.com/combos13.html

look at combos 94 and 95.

they use a 350 with the 252H and 268H compcam with 190 afr heads and 9.5:1 cr.

the 260h is right in the middle so should make 364hp at 5200 and 400ftlbs at 3950 rpms (average of 94 and 95 dyno). then multiply by 1.094 since you have a 383 and the power should be 398hp and 438ftlbs with a 260H, 383, afr heads, 9.5;1 cr. not bad for a smooth idling cam that cam pull a 2.73 gear with a stock converter.

[BillyJack669]

With all this talk of lower compression, little cams, etc... am I gonna be able to outperform an 07 hemi dodge ram truck when all's said and done?

[454C10]

depends. how fast is the hemi?

new trucks have more gears to work with so they have a big advantage over a truck with a 3 speed auto, stock stall, and a 2.73 gear.

gears help a lot! you can make your old truck very fast with a 4.11 gear, 3500 stall, and a big cam (305H). But driving it everyday will not be pleasant. rough idle, real bad mpg, lots of rpms on the highway.

I would guess a 1/2 ton chevy truck would run a low 15 second 1/4 mile at 95 mph with a 400hp 383 and a 2.73 gear. is that fast enough?

[BillyJack669]

Another question: I'm trying to measure the piston to depth height. I don't have a depth micrometer, but I put various feeler gauges together on the surface of the piston in different combinations until it felt like there wasn't any difference in height between the deck and the feeler gauges. Is that a decent enough way to measure it for the purposes of approximating the depth or should I plunge for a depth mic that i'll probably use once?

Also the guy at Arias said my pistons probably are -2 to -3cc with the valve reliefs.

[PatM]

Or, try a dial indicator and a mag base. Set it up kinda like a height gauge. You'll find lots of uses for a dial indicator over the years -- like checking runout on you brake rotors.

Only about 25 bucks or so at HF, IIRC.

Pat

[turbolover]

Using a straight edge and feeler gauges will get you close enough if you are careful. Even a dial indicator can be wrong if you're careless.

[techinspector1]

Originally Posted by BillyJack669

Another question: I'm trying to measure the piston to depth height. I don't have a depth micrometer, but I put various feeler gauges together on the surface of the piston in different combinations until it felt like there wasn't any difference in height between the deck and the feeler gauges. Is that a decent enough way to measure it for the purposes of approximating the depth or should I plunge for a depth mic that i'll probably use once?

This is a perfectly acceptable way to measure piston deck height. But you want to eliminate piston rock on the pin. As you stand at the side of the block, measure at 3:00 O'Clock or 9:00 O'Clock. Measuring at noon or 6:00 O'Clock will allow the piston to swivel on the wrist pin and give you an erroneous reading.

[BillyJack669]

Good tips fellas,

I went to HF this evening, bought the gauge and the base and set it all up, got a reading of .030 piston deck height. If I put this into the calculator with the bore, stroke, gasket size of .039, piston volume of 3cc (for the reliefs) and 64cc chambers I come up with 10.627 to 1.

Did I do it right? Does it change anybody's opinion/suggestions?

THANKS!

[oldbogie]

Originally Posted by BillyJack669

Good tips fellas,

I went to HF this evening, bought the gauge and the base and set it all up, got a reading of .030 piston deck height. If I put this into the calculator with the bore, stroke, gasket size of .039, piston volume of 3cc (for the reliefs) and 64cc chambers I come up with 10.627 to 1.

Did I do it right? Does it change anybody's opinion/suggestions?

THANKS!

My calculator drives 10.527 with 4.166 bore gasket. Answer pretty close enough to yours.

Bogie

[redride]

In my first 383 I used World Products heads and loved them. You can get them for around $1100 a pair complete and I think if you look around you can beat that price. You can not go wrong with these heads for the money.
http://www.worldcastings.com/product...ron-heads.html

[BillyJack669]

Hey all,

Getting back at it now that Christmas has come and gone.
Recap: 383 short block with flat top (w/valve reliefs) pistons .030 in the hole, 10.5-6 compression with 64cc chambers, 9.x:1 compression with 72cc chambers. Building for torque in a 77 GMC pickup that currently has a th350, open diff with 2.73 gears (to be swapped to either 3.42 posi or 700r4 with 3.73 posi).

I'm now looking at Dart Iron Eagle or IE Platinum heads either 180cc/200cc runners or Dart Pro 1 aluminum 180cc heads. I've decided to increase the chamber size if I go with iron to 72cc chambers.

I've also changed direction down to a XE262H cam.

Any opinions on the heads AND cam selection will be welcomed.
I'm concerned about intake runner size. I'll never rap this out beyond 5500rpm and my reading has got me thinking 180's, but y'all are the experts.

Thanks!

[cobalt327]

Given the RPM and cam, I'd go w/the smaller runner. Be sure to take the shorter cam timing into account when you select the compression ratio- an earlier closing intake traps more in the combustion chamber and will call for less static CR than a longer duration/overlap cam.

[BillyJack669]

Cobalt,

What do you suggest?

I calculate the dynamic CR to be 8.8:1. That sounds a bit high to me for pump, shouldn't I try to get down to 8:1 dynamic? Or are you referring to something else? EDIT: Will the magical properties of aluminum keep the higher dynamic compression ratio from detonating, or does that only apply to static compression ratio?

Thanks