What is the Best Rod Length for a 383?

[81Cheyenne]

I'm building a 383 for my C10. Is it better to use 5.7" or 6" rods?  I have a chance to buy a new crank that uses 6" rods at a reduced price and wanted opinions on rods before I bought it. I'll be buying new rods either way whether I get this crank or not.

[VileZambonie]

You'll never notice a difference performance wise. Hardcore racers like to go with a longer rod due to dwell and thrust angle but for a street engine just go with the most affordable balanced rotating and reciprocating assembly.

[nico]

I have 5.7" rods in my 383 and will go with at least 6" next time...  Often times you either have to clearance the rod bolts or get a reduced-base circle cam (that's my choice) and corresponding pushrods with the 5.7's...  For the money, check into building a 396 small block. Just a little more stroke than a 383, but quite a bit more power.

[Captkaos]

What are you building the truck for, a drag truck or street?  For the street, you won't be able to tell the difference as most of you driving will be spent between idle and 2500rpms.

[81Cheyenne]

I'm building the truck for the street. I'll be using it for hunting and fishing. Pulling a boat (occasionally with a slide-in camper on the back), hauling my motorcycle,goofing around,etc. I like the idea of the torque that a 383 will give me on hills,boat ramps and so forth while pulling some weight.

[Captkaos]

If that is the case, I would build the cheapest rod configuration and put the money elsewhere for longevity/dependability.

[VileZambonie]

Yep just go with what's most cost effective. If you buy a matched set you most likely won't have any major clearance issues and the cost will be much lower. I'll be building another one very soon with some Vortec heads. I will post the whole build when I do it but I'm also going to go the more cost effective route.

[Blue 82]

Some pistons (for 6" rods)  have the pins running through the oil ring area

[Blue 82]

here's a good article from many years ago
it gives a few tips on how to get a handle on detonation
I think this article is more important now, with the price of fuel heading toward the sky.
a few bucks spent on machine work and attention to detail will pay off in the long run.

http://www.chevyhiperformance.com/howto/47075/index.html

here's a torquey 383 that might be of interest
http://www.chevyhiperformance.com/techarticles/148_0207_ht_383_chevrolet_crate_engine_build/index.html

[comp]

i'm going to use 5.7's

[81Cheyenne]

here's a good article from many years ago
it gives a few tips on how to get a handle on detonation

Speaking on detonation....(Maybe I should start a new thread what do you think Capt?)...I'm probably going to go with 6" rods since I picked up a SCAT 9000 that uses them.  I have had conflicting opinions (from guys whose opinions that I trust) on whether I should go with flat top pistons or a dish.  I'm using 64cc vortec heads. On second thought, I WILL start a new thread on this one.

[VileZambonie]

Just calculate your compression ratio. Figure out which pistons you have available and find out what the -cc volume is

[81Cheyenne]

Just calculate your compression ratio. Figure out which pistons you have available and find out what the -cc volume is

Yup. Done that already.  I guess the question is what's the max compression ratio that will run on pump gas and still give me plenty of power with this setup(vortec,383,C10,etc)?

[Captkaos]

I would strive to stay at or near 9:1 unless you are going with aluminum heads.  By pump gas are you talking about 87 or 92?  I would build it to run on 87 it it were mine.

[Blue 82]

here's a good article from many years ago
it gives a few tips on how to get a handle on detonation

Speaking on detonation....(Maybe I should start a new thread what do you think Capt?)...I'm probably going to go with 6" rods since I picked up a SCAT 9000 that uses them.  I have had conflicting opinions (from guys whose opinions that I trust) on whether I should go with flat top pistons or a dish.  I'm using 64cc vortec heads. On second thought, I WILL start a new thread on this one.

Using a flattop with 64cc heads with a .030" over piston .025" in the hole will put you at 9.8:1 with a -5cc flattop with a .040" gasket
If you zero deck it it's close to 10.8:1

Deck it .015" and use a dished slug for better detonation resistance... with the piston .010" in the hole that gives you .050" piston to head clearance with a .040 gasket.

some people say that .050" piston to head is tight, but I've run the slugs .003" above the deck with a .039" gasket with no problems in a 383 for a Ski Boat. You gotta use hypereutectic pistons for that, and keep the piston to wall clearance tight.