I'm picking up an lt1 block today out of a 94 Camaro and I was wondering if I should go 383 or just leave it 350. I'd like to get 400hp to the wheels if possible. I know either way a good set of heads and intake are in my future but I didn't know which would be a better/more cost effective way to make the power out of something that will be daily driven. Opinions and suggestions are highly welcomed. Also any swap tips would be nice to as this will be my first ltx swap.

 

leave the rotating assembly stock and spend all your money on the heads/cam/intake. you can make nearly 100rwhp more than a 383 with stock heads.

 

Both 383 and a H/C setup on a stock rotating assembly are going to cost you.

The stock heads also will not happily feed a 383 so you'd need headwork anyways to get the most out of it.

Getting near 400rwhp requires head work, HAS to happen. And it requires a fairly healthy cam even with ported heads. You are going to be spinning a 350 size engine in the 6000-6500rpm range to make 400+ at the wheels depending on how well the heads flow.

6500rpm is near the upper limits of most stock LT1 shortblocks. I don't know if I'd want to take an average LT1 block past 6700rpm.

When choosing a cam for my heads/cam swap on my stock LT1 block I didn't really want to rev it past 6200rpm all that much. Now its knocking so I'm having a shortblock built and I stepped up the cam with more duration.

Talk to Lloyd Elliot, and Advanced Induction. AI is better, but more expensive. Lloyd is cheaper but still proven.

 

Had a SBC 383.
Strong, but loved the fuel....always had to feed it.
Also made lots of heat... all those BTUs from the poor mpg....they had to go somewhere
Thirsty and hot were never in any article I ever saw... my take would say a 355, and a bit less HP.

If you want painless HP, maybe you should look to a LS

 

If your goal is 400whp and you already have a running lt1 in the car its often cheaper to upgrade the lt1 than jump ship to gen3 unless you get a good deal on a donor car.

If you want to go beyond that then it gen3 becomes the cheaper route.

 

Put some HP bearings in that shortblock since the factory bearings are junk for what we do add an LE cam/heads combo and enjoy that Lt1 without a bunch of cash invested....
Are you going to have a manual or an auto? Autos are harder to reach the HP goal you have so up the compression Lt1s have No problem being pump gas friendly at 11.5-12.1 compression and that is where you will get the power from!
In short, deck your block O deck height, mill 15-20 thousandths off the heads, rebearing it and change the oil pump to a STD.volume high pressure pump instal Lloyd's Le2 heads and cam package, have the intake port matched, 52-58mm,30-36lb injectors and 1.6 roller rockers with 7/16 studs, chromoly or hardened 7.200 pushrods.
Automatic use 3.73s
Manual use 4.10s
Get that pcm tuned and you will be above your goal!!!!!!!!

 

my LT1 has what most people in the LT1 world consider the best 200cc ported factory casting heads you can get. 236/248 nitrous cam, and the rest of the supporting valvetrain. single plane intake. everything else on the engine is stock parts, and bearings/rings are oem replacements. 425rwhp sae through a th400/9" rear/28" slicks on a dynojet.

 

I'm definitely going with a t56 and plan on running 4.10s in the rear. I'm liking what I see on the LE site especially the LE2 heads and cam combo.

 

Take note though, you'll only see those numbers with all of the bolt ons like Throttle Body, cai/filter, full exhaust....

Most of those #'s are 6spd numbers too.

 

I had planned on doing all the other go fast parts originally just was unsure on the heads and cam. I found a lot of good options on both the LE site and AI.

 

If you can afford it AI is definitely the better of the two options, but takes more $$$.

Cam wise between the two, I don't know which is better. I know that Lloyd recently switched to Lunati's asymmetrical lobes for his cams. Aggressive lift ramp on the opening side and a more gradual ramp on the closing side.

I actually just ordered his new cam for my build since I am rebuilding my short block and will trust it with more RPM's now.

Went with his 231/239 cam on a 110LSA. Should peak in the 6500rpm area and still carry some power even beyond that with ported heads.

Still have my 226/232 camshaft which i'm trying to sell, but had no bites yet. Maybe I'm asking too much but its never even been installed or removed from the packaging. Figured I'd get lowballed anyways.

 

PM me about your cam (the one for sale) Id like to dialog with you about it.

 

PM sent.

 

Got it ??? I'm gonna have to think on that one, I thought it was a LE cam.

 

It is. Lloyd designs the cams but compcams grinds them. It's not an off the shelf grind.

 

ok here is my on the issue. a small block is limited on HP by only 4 key components, 1st: AIR IN "intake, 2nd: AIR OUT "Exhaust", 3RD HEADS, 4TH CAM, In that order, you can get 500Hp out of a 283 with enough $$$, the 383 is a good engine for torque "In my opinion" I have had a 400 that turned 8500 with 450hp + but 3mpg kind of sucked. if money is no object the shoot the moon, shoot you will have crazzy braggin rights. other wise do your research and build smart.

 

I did not know that, I'll contact you later, gotta get out of here.

 

if you made power to 8500 with a 400, hp would be way, way, way more than 450hp.

 

Here is my take.

Comparing a 383 to a 350, you will see better torque & drivability from the 383 vs the 350 if built to a similar power level.

As for the need for good cylinder heads, this is correct.
You can get good power with a set of LE ported stockers to 6500 on a 383.

Keep in mind the LT4 package made over 450hp with stock LT4 heads and their
hot cam which was pretty mild. The LE heads should be better than the stock LT4's.

For comparison, I built a 9.3:1 low compression 383 LT1 that was destined for a blower. Used a small 220/230 blower cam, CNC ported stock heads & it made over 400 to the tires with an automatic, normally aspirated, through cats. It still averaged 18mpg & ran high 11's. in a 94Z28. This was a test to see how it did before the blower was put on. Obviously with 11:1 compression it would have done much better.

As for fuel mileage, the cam choice will likely hurt you more than the cubes. If you build enough torque, you can leave the trans in 6th & keep the revs down.
With 4.11's I would not expect this to be a problem, but thought I would throw it out there.

If the stock bottom end is good, then save your money & build the top end with good parts. You can always forge or stroke the bottom end later if you desire.
You power goal will not be a problem.

 

ya probably right I did not get to put it on the dyno, but it would pull the front wheels about a foot and hold it through 1st gear. way crazzy!!!

 

Man my 11 to 1 383 made 392 on 10th pull at 204 deg coolant and 90's deg shop air lol big cam and afr 195 heads. Doin 400 with less cam and compression is impressive lol

 

real impressive!!!!