i have a L98 with 115,000 miles and a noise in the lower end under load and i want to rebuild but im looking for 325 at the rear wheels maybe 400 in torque. i just dont know what to do their are so many different things these are my current mods if someone can help me figure out what to do.
air foil
under drive pulleys
b&m shift kit
flow master muffler
400 h.p. fuel pump
bbk fuel presure regulator set @44lbs
timing advanced to 10*btdc
hollowed out cat
new 2 1/2 ex. pipe
new mass air meter
new computer
new ignition module
new plugs
polly graphite trany mount
new m.a.f. relay
ported upper plenum
a.i.r removed
160,fan switch
180,thermostat
high performance ignition
homemade air induction

 

I'd start with a set of headers. 1-3/4" if you wanna make 325 rwhp.

 

Okay, if it were me:

I would put together a 383. I would use Vortec heads along with the mandatory SDPC base intake. Siamese port the thing and port match it to the heads. Get some large tube or, better yet, siamesed runners. Port the plenum, use a larger TB. For a cam, use about a 215-220 intake duration, 220-228 exhaust duration, as much lift as you can get! Compression ratio of 10:1 is good, forged pistons if you can afford it.

Of course the power comes in the tune. Learn to burn proms. Lots of info on this board and as you will soon learn, many other sites on the net offer info on ecm tuning.

I recommended the Vortec heads because they are a great head for the price, $500 for a complete set!! There are better heads out there but if you are limited to about 3 g's then you can spare on the high dollar aluminum units like AFR and the like. There are also other companies that make affordable heads, PRo and World Products, Dart, etc....However, you will need to research results from these componets. I have read about quite a few 400 HP engines using Vortec heads.

Good luck

 

Stay with a smaller head. Don't go out and buy 190 cc heads. You will not have enough motor. I am using ZZ4/L98 aluminum heads. Tons of work though. Did most myself. I myself am using the LT4 Hot cam. Very mild cam. Part # 12513151 is a GM motor. Standard bore 350 with forged crank, hyper pistons, PM rods, and warranty. Cost around 1500.00 . I am using a SuperRam upper and lower. Lots of port work. Get the compression ratio up. I'm at 10.9:1 . Still very streetable. I am making more power than your asked for. Tons of torque. All this with an Ed Write tune. Three tries though and lots of dyno time.

 

if you want some good torque, go with 1.94 valve heads and 1'5/8" headers, long tubes with 3inch collectors and all the collector volume you can get, and that alone should get you soem good torque.

 

tell me what you think i wa gonna go with this set up for now edlebrock 202 heads,LT4 hot cam,10:4:1-10:8;1 compression,1 5/8" headers and a 3" dynomax cat back and im gonna port all the stock TPI intakes for now until i can afford another intake and a chip.will this give me 300 rwhp or so for now? will i be happy with the power form this set up?

 

what about the cam?

 

its ses LT4 hot cam bro.