ChrisUlrich

Lets take my numbers for example, 302/304 at the wheels

I reinforce my bottom end, bore and stroke it... 383 with 11-1 compression. Splayed 4 bolt, balanced, etc... a nice machine job.

That doesn't really increase the numbers all that much right? Kind of just supports the mods on top of the motor?

Also, how much can a T56 tranny hold up to? Before that **** falls apart?

Purplemaroz28

im guessing that would do more than support your top end. I would assume that you would see alot of gains with that much work done.. And by the way having the engine splayed to 4 bolt would almopst be pointless unless your making 450+ hp to the wheels or running a s/c save yuor money and spend it on a good crank pistons and rods. just my opnion thought so...

ZMaster

I have no personal experience, however, i have heard that splayed mains is the way to go for a power adder or for high rpm. Whether or not you want ot spend the $$ is up to you, but i would at least get studs with a 2 bolt main.

Ian

ChrisUlrich

I plan to spray to over 450+ rwhp... top end right now is built just with stock heads...

This would it the setup... summarized version.

XE 227/233 Cam on 114lsa
1.6rr
stock heads
383 forged bottom end with splayed 4 bolt
11 to 1 compression
Pacesetter LT's

Before 383 bottom end and LT's, car made 302/304

SS MPSTR

Splayed or straight 4-bolt mains...doesn't really matter - both are suitable for high hp applications.

ChrisUlrich

I was going to go splayed...

but what does the 383 forged bottom end and raising the compression... what does that do for numbers?

1racerdude

A 383 with a descent set of heads and intake tract with the right cam would not need hose for 400RWHP and maybe 450. Ya have a small cam for that much RWHP without hose.

ZKrazed

I am turning 430hp/454tq (flywheel) on a supposedly f'd up A/F ratio. So I hope to free up more power through a better tune. Check out my page in my sig and the 3'rd page has all my engine specs and what not. I too plan on running a 100-150 shot of NOS in the very near future. But go with forged internals, but if you are goin rebuild parts on the engine you might as well do it right and get a better set of heads either AFRs, stock or get LT-4 heads and send them to Lloyd. I wish I would have had the extra cash to do LT-4 heads LE3 style. It sucks to drop a lot of money and beat 99% of what is on the road but then you come across a few highly modded LS1s or 03/04 Cobras and lose by a few cars.

ABA383

I think I'm in your ball park for rwhp/tq with a 383 n/a with an A4. My combination is as follows:

4 bolt block (Corvette replacement)
Callies crank
Oliver billet steel 5.85" rods
JE forged pistons
Comp ratio 11.2:1
LT1 heads CNC/hand ported by LPE, then by E.B. Porting 2.00/1.56 valves
LT1 intake hand ported to match head ports w/ 30 lb injectors
58 mm LPE TB
Joe Overton smallish cam 226/234 @.050 .560ish/.560ish" lift
1 3/4" LPE shorties with a Borla CAT back run wide open with no plates.

It made 400rwhp/430rwtq with a rich 12:1 a/f ratio on a base tune from Joe Overton and an ejected driveshaft at 6100 rpm . With 12.6ish:1 and a good tune it should pull 420/450 at the wheels. Just recorded 21 mpg on a recent highway trip, too! You will make more with an M6. You might not need to spray unless you want to do 500rwhp.....

--Alan

WS Sick

If you save some money by going a cast steel crank and forged "I " beam rods with forged pistons you could have your heads worked. Without better flowing heads you'll not gain much power N/A but you'll gain alot of torque.

97WS6SCharged

He should pick up a little hp, but as mentioned, torque will be up all the way through the rpm range. Stock heads on a larger displacement motor should up the velocity of the incoming air quite a bit, especially at 11:1 compression and that conservative cam.

Alan, that's a really impressive combo you have there. How exactly did the driveshaft eject it self? Got any pics of the carnage?

Chris, don't forget, adding 4 bolt caps to a 2 bolt block is definately not a cheap route to take. You're going to pay for the caps, the stud kit, time to install them, time to align bore the them, not to mention you need a special shorter timing chain. My timing chain was over $100 bucks, and that was slightly above cost. Just something to think about if you're still going to sell the car.

1racerdude

Small heads may up the velocity,but ya need volume to make HP. The cross sectional area has to match the CID andRPM. Small heads run out of wind in the upper RPM's.

ABA383

97WS6...Thanks...and sorry no pictures, I was way to pissed to think about pix. We are not sure what went first. Its a toss up between the rear u-joint and the Spohn trans mounted TA putting too much stress on the 8 year old tail shaft. The aluminum 1LE shaft broke right in half like you cut it with a knife. The front was looped, but the rear half went everywhere, first it cut the floor in a few places, then took out the emergency brake brackets, then the rear yoke, then a section of pipe from the Borla cat back, and the TA where it smacked it real good, finally exiting the underneath to come to a rest in the middle of several $100,000 Vipers... (Dyno was at Heffners in MD) Thankfully, no people or Vipers were harmed...

Its all back together with a killer new Spohn TA mounted to the cross brace location with TWO loops, and a 3" steel driveshaft from A1 in Baltimore that FBC uses in their 9 second cars. I am now an advocate of getting the TA off of the trans at all costs, and having front AND rear driveshafts loops!!!

The car went 11.70s @118 for 10 years with the original LPE set up and tiny cam on BFG DRs. We are hoping for low 11s @ 120 with the 12 bolt and some sticky tires...we'll see...

--Alan

1SlowFormula

So I guess you found a shop to build it for you. Where are you getting it done, if you don't mind me asking?

BTW, if you had 302/304 prior to the rebuild then my guess would be with all the same bolt-ons and a new tune for the increased displacement you should see about 330/332.5, this is just my guess because the displacement grew just under 9.5% going from 350-383 so your power should increase bu about the same percentage. Again this is my asumption, but eveyone says how you make (x)hp/cube, then that amount of hp should rise when cubes rise right?

slomarao

the extra 33 cubes and .5 of compression may give you 15-20 horses.