noboostnogo

On friday 22nd when i went to the dragstrip i raced my 89trans am and managed to get a 13.4 with the new modified LT1 manifold but apparently my block could not handle the power that the lt1 had to offer so it started smokin alot.

Im debation on whether i should go with a 383 or a 355, my current setup is a stock bore 350 4bolt, flat tops and some 64cc ported truck heads and as stated above the lt1 intake and some summit shorties, 24# injectors, hi-pressure fuel pump and still rocking the MAF, and a cam with a duration of 212 and 218 and a lift of about ~.488 + 1.6 rocker arms.

My main concern right now is the bottom end i know my heads will not be able to handle any well built engine but i cant afford to go all out right now. My goal is to go mid to low 12s. Can you guys help me out with this build and inform me of whats good and whats not. As i said before i am unsure of which route i wanna take as far as displacement.

Thanks in advance

James Montigny

iTrader: (13)

You can go low 12s with a mild heads/cam car and stock bottom end without much effort.
Were you smoking from a blown head gasket, or did you crack something?

Fixxer99TA

iTrader: (5)

Yes, what exactly happened? And like James said, its not too hard to go low 12s with even a mild heads/cam setup.

But if you really want to go bigger cubes, I would say go with the 383 as you will want it eventually anyways

noboostnogo

well i havent taken it apart just yet but i think what happened is that when we assembled the engine since it was just a cheap build we didnt measure any clearances or anything, the block had like 150ish miles on so the bores werent quite round, still we put new rings bearing and a set of flat tops, i'm assuming since the ported lt1 added about an extra 40whp over the stock tpi my pistons started lettin oil through at higher rps so it smokes like CRAZY, or a vavle seal that couldnt handle the rpms but idoubt that. It only smokes at 4k or higher rpms

noboostnogo

i also forgot to mention that my engine is a sbc and not the lt1 with reverse water flow, i just have a modified lt1 intake on there, i hope this is the right section for my thread.

James Montigny

iTrader: (13)

I see, that explains the "ported truck heads" LOL

I see it as an opportunity, since the engine is apart anyhow.
If you have room in the budget for a crank, the 383 is a nice upgrade.
The extra bottom end grunt makes it fun to drive

The problem being the heads, I don't know if they'll flow enough to feed a 383.
Did you happen to get flowbench numbers when you ported them?

You might get better answers from the guys in the SBC section
https://ls1tech.com/forums/small-block-big-block-chevy-specific-92/

You can also try thirdgen.org, there is a huge wealth of info over there.

Fixxer99TA

iTrader: (5)

I dont see why this wouldent be ok, its still kinda an LT1

I say 383 though, if your going to have to take it apart again.... May aswell make some decent gains right?

noboostnogo

yeah i was really considering the 383 but i'm kinda worried about my heads, they have not been on a flowbench i actually ported them myself and i probably port them more once im puttin everythin together.
I know both the 355 and the 383 would benefit abunch from new heads but as of right now i wont be able to do it all. What i would like to build right now would be the block.

I think i am considering the 383 over the 355, i was thinking keepin the comp. around the 10-11ish area with 5.7 rods? what cam would be a good one to match the setup?
Oh, i do have a 3200 stall converter.

96lt1m6

iTrader: (31)

A fellow member had a similar set up,it was pretty mild but extremely effective.NOTE:his runs were in vegas 2400'+da
97 z28,cam ONLY,no weight reduction..
3.42s(stock 10-bolt)
hoosier 27"QTPs
3000 stall/4l60e
jet hots,true duals
PCM 4 LESS tune(obd1 conv)
52mm tb,255lph
227/233 comp cam
1.6 rr,new springs 918s
12.5 @ 113

noboostnogo

yeah that sounds about right.... for an lt1 engine, lol, a small block w/ that setup would never see 12s, i have 3.73 gears. i was hoping to go 12s with a mildly built 383.

noboostnogo

any other suggestions??

Puck

iTrader: (17)

11:1 cr will be a lot more difficult to tune properly on pump gas with an SBC then an LT1.

You really should try the third gen section - even though you have an LT1 intake its not an LT1 engine and will like different things parts wise. Things like compression ratio, proper cam specs, what type of ignition to go with, etc will all be very different on an LT1 then an SBC considering the differences - and matching the proper parts for your engine and goals is extremely important to make a combo do what you want it to. That is not even counting the huge differences in the cars bodies and what will need help where in each platform(like the wheel hopping LT1 that kills rear ends and the flexable third gen body and chassis - especially those weld popping, body panel dimpling t-top third gens!)

It is hard for us to give information since besides being a different engine, we do not know the important specifics needed to plan out a build like head flow numbers, gearing, mainly street or track, etc.

If budget is a big concern and it is not mainly a street car a quality 355 refresh with aggressive gearing and a sticky tire will be fun at the track, and won't be too dangerous with a mild street rebuild like you are describing...

Sadly there is no reliable and cheap way to go fast, and I suggest a lot of planning, reading, and most importantly checking out people with similar builds at the local tracks, where you can get first hand information from other car owners with the same cars on what has worked for them or has not.

Good luck on the build!!

LebaneseShowoff

iTrader: (6)

Honestly, your best bet might be just an LT1, sell all the SBC stuff and pick one up at a junkyard from TB to oil pan with ECM for about $250. And work with that. Nothing wrong with SBC's, it's just easier to get more performance out of a newer engine.

03 snake

iTrader: (28)

383 is a great choice if you can swing it.. Lots of potential to grow with down the road too..