hey guys Ive been undergoing a tear down and build for awhile now. ive been taking it one piece at a time. the car is a 91 l98. heres what im working with so far...

block 91 l98 .030 1 piece rms
4.030 flat top pistons and rings
stock rods.
all arp bolts connecting rod, cylinder head, etc.
99 tahoe vortec heads 906 (alex parts .550 springs and retainers)
edelbrock vortec intake(mega ported)
slp runners(mega ported)
Ported plenum
ported throttle body
1.52 comp cam pro mag rockers
lunati 60121 cam .515 int .530 exhaust
bbk pulleys
2300 torque converter
24lb cobra injectors with south bay adjustable fpr and diaphragm
Streetfire distributor, ignition box, and coil with 8mm taylor wires.
Slp shortys, to a 3" Borla
and Soon to be burned chip from pcmforless.
sure theres more but this is what i can think of of the top of my head.

now that my block has been taken .030 over, which was an unexpected step in this build im looking towards getting a new 383 crank..go big or go home kinda thing. heres my question.

does it have to be an internal balance crank if im having the entire assembly rebalanced? the reason i ask is the ones i find (internal) that are reasonably priced are only rated for 400HP where as the external...which are a little cheaper are rated 500+?

any help and or suggestions are welcome and appreciated! Thank you in advance... Trae

 

You're not going to be able to just throw the crank in there because 383 pistons ARE different.. otherwise you'de need to do it the oldschool way and jump down to stock 400 SBC rods to make up for the difference. Better off just buying a whole kit and keeping it simple.. otherwise, just get new pistons for what you've got now.

There's not a huge difference that you'll see by any means between the two, but I wouldn't want my balancing to be done externally if I had the choice. The price between the two is minimal, really. What parts are you comparing? Ratings are always skewed because there's a lot they don't take into account for.. like RPM, for example. I wouldn't worry about ratings and just focus on getting something that is a quality part.

 

so there is a difference between pistons for a 350 and a 383 regardless of the bore.(ie.both 4.030)
here are the pistons I bought...http://www.ebay.com/itm/390542644736...84.m1439.l2648

and here is the crank I was looking at. A internal/external balance crank from scat.
http://www.ebay.com/itm/200720335730...84.m1423.l2649

these together with stock rods would not equal a 383?

 

ahhhh nevermind I see. different stroke length.

 

And, don't forget about clearancing the pan rails a little to a lot depending on rod/bolt combo. Also, maybe a small base circle cam. There's lots of little pitfalls with a 383, which convinced me to stay w/a 350. Most don't pay too much attention to these things and get away with it. But, I usually have lousy luck. Just my

 

should I have to worry about clearance issues using the stock rods and arp wave locs?

 

What is your goal with this motor? That's really the big question. A 383 is a good motor as are the heads you have on your current motor now.. but that 383 is held back by the cam and heads if you're trying to make serious power. It's not a big deal if you just want a nice street bruiser, but you never know. I started out just wanting 350 HP and now I'm just under an honest 500 HP. It never stops, heh. Doesn't take a 383 to make good power if that's what you're after.

 

I want an all out street beast. but I do drive it daily. I would love to see 11's but i realize 12's are more realistic. well all this started when I lost my Transmission. then i was given a LT1 cam from a coworker. in gathering parts for a cam and trans swap I decided there probably wouldnt be much to be gained with 1.6 rockers and a LT1 cam. so I decided to just take my time and built what I want a fun Daily driver thats most likely going to get me into some trouble.

 

The only way to know for sure is to measure.

 

I guess ill have it looked at when its at the shop. hopefully im good. cause Im already a few grand over budget haha

 

Chances are you're going to need clearancing. Maybe not a whole lot, but you'll most likely need it.