Rlncoalctd

iTrader: (3)

Hey guys,

Originally I was going to run my stock short block ls1 with the following parts:

Ported TFS 215's with 60cc chamber
RapTR cam 236/242 .615/.615 on a 111
37lb injectors
Fast 90/90
Racetronix fuel pump
and the mods in my sig...

What do I have to look forward to by going to a 383-396 range?

I have a 2004 ls1 longblock I would be doing the build on, I hear these have more sleeve material.

Do I just sell the parts I have accumulated and start from scratch on the bigger cube engine? Do I use those parts with the 383 build.

Or

Are the gains so minimal that its not worth the $2,000 to do the forged 383 setup.

The reason I got to thinking all of this is I keep hearing you cannot do rod bolts without resizing the rod ends. In that case I would just rebuild, but why go back to stock?

Thanks in advance!

supersick99z

iTrader: (66)

Benefit in going with the 383 is going to be your TRQ increase and HP will not be significantly higher. Regardless of numbers, in the end it's worth it for the simple fact that you now have a forged motor to throw power to in the future with a power adder of some sort with no worries. Good luck either way!

Rlncoalctd

iTrader: (3)

That is kind of what I was thinking, a decent gain in torque and its ready for some big nitrous if I want to go that route.

How much does a standard ls1 rebuild cost if I decided not to go forged? I never really planned on spraying do to my lack of experience in it and I dont think this car will ever see the track.

Troy5061

iTrader: (19)

Going to 383ci will usually not provide a significant boost in peak HP numbers from a similar 346ci engine. What you do get is more torque under the curve and more power at lower rpm which provides for greater driveability. You also wouldn't have to turn the 383 up as high as the 346 to make the same power so thats usally easier on valvetrain and rod bolts, obviously a max effort 383 with trick flow heads and a huge cam with a fast 102 you could turn 7000 and still make power but thats cubic dollars, I know my 383 will more than likely run out of breath at 6500.
I did a 383 because I couldn't see ripping the k member out to remove the engine and trans/tearing the shortblock down just to put stock **** back in. Now I have a forged 383 that I put the juice on if I want or down the line throw some 317 heads and a .060 headgasket and run a procharger.

RonSSNova

iTrader: (3)

A 383 will be better everywhere. If you were to simply only change the stroke, and nothing else, the power won't grow as much, but the torque will. This is because the cam for the 346 isn't optimal for the 383. However, if you change the cam to go with the cubes, you get both. The 383 will take a bigger cam yet idle the same as the 346 with a smaller cam.
It is a win win situation.

I was told the same thing with my 454 going to a 496. But we matched the cam to the new CID and made 140 more hp. Ended up at 700 (flywheel) at only 6200. My 454 actually had a higher peak rpm.
Car went from 10.90 to 9.90's and gained 12mph in the 1/4 mile. On pump gas at only 9.4:1

I'd love to build a 383 in the off season for my Vette.

Ron

mark21742

You might not see it in peak numbers, but Ron is exactly right....for instance in my 408 my 255/263 cam acts like 228 in a stock cube motor. It is amazing how much the extra cubes just eat up the larger duration and you get a win win everywhere with the big hit of power coming in sooner and even a more stable idle.

So again, numbers really don't do the 383 justice, till you look at the entire rpm range. Plus if you later decide to go with a 402/408 you can use the crank and rods out of the 383 and just get pistons/rings to fit the new bigger bore of the new block

Rlncoalctd

iTrader: (3)

Thanks for the input guys. I guess if I am going to go 383 I should match a cam to it.

Whiteaw57

iTrader: (2)

the cam you have is fairly large. It would definitelyeat it up a tad but I dont think it will run bad by any stretch of the imagination. Its up to you if you want to spin it high and make great power or keep that cam and have great driveability and a lot of power still, but a little less pull up top

Whiteaw57

iTrader: (2)

I don't have a 383 but I have a lot of general knowledge on this stuff. I really don't think that Raptr will be a bad cam in a 383. especially on the street!

Troy5061

iTrader: (19)

That RapTr should be a good 383 cam, I was gonna say high 230s intake duration and low 240s exhaust duration and then I saw what you had listed. I went small 230/238 .600/.600 due having a set of low milage Pac 1518 singles I just bought, didn't want to have to buy doubles and a lighter valvetrain to run a bigger cam right now, even you can go bigger but that will work just great I think.

mark21742

I had a 238/242 in my stock cube motor and it was on the big aid for daily driving, then I put it on my 408 and it was too small lol so the cam you have should be perfect in a 383

ausls1

I was going to forge my 346 but for the extra price off the crank i decided to go the 383 route, mines close to finished, just got my ported 241 heads back and hope to have the motor back together and tuned with in the next 3-4 weeks hopefully, i'm using a similar sized cam a comp cam 235/243 .621 .624 113 lsa, will let you know how i go, tuner said will be good for the street where mine will mainly be driven, my cr will be 11.1-11.25:1, iv also gone a little extra and got a fast 102/102 setup and got 1-7/8 headers.

99fbodyTA

agreed. otherwise sounds good to me

christiandoy

iTrader: (1)

I'm also doing a similar build
Picking up the rotating assembly off of Texas speed
Went with a mild 230/230 comp cam for now .591 lift
If you have any questions feel free to pm me as I've done a lot of research on the 383 build

yyz28

iTrader: (3)

MS4 in my 383, purrs like a kitten.

garygnu

maybe consider a cam from TEA to match the head flow.or look at the bigger EPS cams.