Im got 2 good deals at the moment and cannot make up my mine on whether I should go 383 or 398, My main concern is which would work better with my unported intake and heads, 2.02 1.60 valves,HOTCAM KIT,Chromolly pushrods,
lifters, everything of my heads is upgraded. This is what I get on the
383...

LT1 block
eagle cast steel crank
eagle I beam rods
clevite bearings
srp forged pistons
perfect circle rings
block machine work
balanced
assembled

and here the 398 info on what I get

398 Ci .40 overbore LT4 Block
Decked/Honed

Lunati Nitrous Pistons, 4340 Crank, 6" Rods, Chromolly Rings
Crank was dynamically Balanced on the block with the flywheel and ATI Balancer.
ATI Balancer
AFR Hydra Rev Kit
242/248 @ 112 LSA Cam 575/600 lift
Street Twin Clutch and Alum Flywheel
Canton 8qt Oil pan
High Volume Oil Pump/pickup
OBD I PCM tuned for Cam
LT1 Edit with Cable for that PCM

The 242/248 I heard will not work with my heads because it to big and if that wrong please correct me and let me know but if it is true then let say I put my hotcam because Im in cali so smog issues. But anways which would be good for me in peformance and horsepower and how much do you think.

 

No offense, but you have way too many mismatched parts to go with either kit. There is no way your running 2.02 1.6 valves in unported heads. Unported LT1 castings are just going to choke the crap out of a stroker motor anyway. I would at minimum recommend fully ported LT1 castings or ported LT4s for any stroker setup.

 

agreed

 

if you plan on running a power adder (quite frankly i never would regardless if its naturally aspirated or not) you do not want a cast steel crank your rotating assembly on your stock LT1 is all forged so why would you build a stronger engine, which places even more stress on the crank and other parts, and put a weaker part in it?

 

Stock crank and rods are cast.... the later LT1 rods are powder metal.

A aftermarket cast steel crank is stronger than the stock crank BTW...

Bret

 

I'd get the 398, then send those heads of yours to A.I or lloyd Elliot. Just my .02.

 

could of swore the rotating assembly on LT1s were forged im no expert and i don't know where i heard it so im probably wrong, sorry

 

No problem just thought I would let ya know!

 

Before the General phased in powder metal rods... they were using forgings. I don't believe Chevy's ever employed a cast rod. Pontiac's a different story though.

-Mindgame

 

The heads are slighty ported but not at it best, I will do porting on my heads and intake but for the time being is which would be perfect NOW. I wanna get my car runnin then save up for the heads and intake porting down the road. I just need some expert help on this situation,

 

Think ya are right.
As far back as '55 with a 265CID.Didn't fool with the "I" blocks much back then,so don't know about them.
We used the stock 283 rods and put the factory 11/32 rod bolts in them for 301's and turned the snot out of them,for that day(7200)

 

A 383 with Loyd's stage 3 heads & cam will make more power than a 396/8 with the same set up. It won't be choked for wind as bad and the 383 will be cheaper to buy parts and get machine work for.Ya also won't be worried about grinding through the block into the water jacket when having the clearance work done if ya buy the right rods.

 

Both of these motors are new and ALREADY built just need to pick one. Well today I went to the performance shop I usually go to and are very known in the bay area in cali but anyways they said I should go with the 398 for the cubes and for the moment run that with my hotcam kit, After I have enough money I would do a heads and cam package for my car with porting. The 398 deal is a steal am I think Im gonna go with that and that shop has never let me down or my buddies. So mostly likely Im gonna run a hotcam in a 398 for alittle while untill I can afford a heads cam package.

 

at 40 over, you may have a marginal block as far as cylinder wall strength, it depends on production tolerances. And it sure will be pretty much the limit for an overbore on that block unless you are very lucky.

Rich

 

Wow.... that is not the best advice I have ever seen. You did get a lot of really good advice in this thread though.