I need to make a big decision on my next build but not sure which way to go. I do know an ls swap will be more expensive and i have nothing on hand to start the project. On the other hand i have my 355 that was built by Xtreme Horsepower Unfortunately that engine took a crap 2 years ago and has been waiting for me to do something with it. This is what i remember the engine had........

355 with srp forged pistons, hypereutectic rods, cast iron crank, comp cams flat tappet cam and lifters, 1.6 roller rockers, aluminum world heads, victor jr. intake with xhp's crappy port match and polish on both heads and intake, holley 750 double pumper, and crappy tune, long tube headers, and magnaflow exhaust.

I also have a nitrous kit that will go in the car for the next build.

After the car was tuned right by a experienced carb guru, the car ran pretty damn good, close to 20,xxx miles later the engine started knocking. Found a rod bearing coming apart, and main bearings showed signs of heat possibly due to lack of oil, possibly oil pump taking a crap slowly.

I basically have everything from the sbc. I will rebuild the engine with a roller cam and a good set of heads and intake if needed, if you guys can help me figure out what to go with. I want to run nitrous as well but need help deciding what to buy for my build. I'd like to run the same internals.

Or do i ls swap and sell what i have. So where should i start guys?

 

If you rebuild the SBC, you will have a new engine. If you swap, you are going to get a used engine that you may end up rebuilding anyhow.

I did a swap to a new LS engine. It was not cheap and there are hundreds of little things that add up. I could have bought a BluePrint 427 with 540 hp for a lot less and been driving the car all summer.

 

I have a built 357 in my '79 Firebird, it's a good motor and platform. It has 12:1 static comp and 11:1 dynamic via the Crane 286 cam. Has worked 993 heads, high flow oil and water pump, Weiand aluminum dual plane intake, and Edelbrock 750 cfm. Have piping that runs off the snorkel down into the front bumper so it sucks in cooler outside air. My only complaint is how fast it likes to suck down Shell 93, but I'm silly and decided to use it for a daily. Of course this was the previous owner's doing.

What I'd have done is take a LT1/T56 out of a totalled F-body and transplant that into it. One advantage to the LT1 is it has the same engine mounts as the older engines, so no custom mounts needed. The other advantage is that the LT1 is always overshadowed by the LS1, so that keeps pricing down. It's also available in OBDI, which makes electrical and dealing with emissions a little easier. Once Opti and the intake gasket is sorted there's really not much more that's a problem. It's a very capable engine, Hell the LT4 Firehawk made 330 hp which is only five less than the LS1 Firehawk.

It's just something to think about anyway, and they're easy to find for not much money. Plus the LT1 has better sounding exhaust over the LS1 with its new firing order, which definitely matters by the way.

 

I used to be a small block guy. But ever since going to the LS, I've never looked back and had a single regret. They just run way better and love to turn 7000+ RPM effortlessly. They are cheap to swap for me, take everything I dish at them and the old SBC to run as good needs more money. That's how it is for me anyways.

 

Technically you're still a small block guy, just of the third generation. I was going to suggest if he really wanted to do a LS swap to look into the 5.3 to save some money.

 

id rebuild the sbc, itll be much cheaper since thats what you already have.

 

I have been researching parts and forums just trying to collect info. And yes i will end up spending more with the ls swap. But i am still unsure. I would love to build my sbc and see what kind of beast can be built, but at the same time having an ls in my third gen would be awesome. I just got my crank turned and would be ready for rebuild but....... i have been reading the 355 build w/ nitrous thread in this section and v8sten you are making me want to sell my bottom end, and purchase a 383 rotating assembly from Ohio Cranks.

 

I have been thinking the same thing when weighing options for my build. The deciding factor for me is the driveability of the LS. Yes it's more pricey but in terms of reliability and mileage you can really get a higher bang for your buck. I still have a sbc in my blazer and am planning the lsx for my Chevelle. I would go lsx if I had it to do all over again for my blazer. Keep the 355 for something else if you come across something. My 383 found its way into my blazer just because of the money I have into it.

 

it all really depends on your bankroll, amount of time you have to get it running and what you already have. since you have a setup for a sbc i would stick with that. unless you want to start all over. a sbc can run real good, but an ls will perform better "all motor" built to similar specs as the sbc because of a better cyl head design. i like them both and have both

fyi i will sell my 383 for $3500 firm ...... pm me if you are interested, im SE of Houston.

i have gone a high 9 second 1/4 mile in a 3250# s10 and mustang with this motor. now it should make more power.

 

pm sent.

 

If you already got your 350 apart by all means do a 383 youll never do a 350 again. They can handle larger heads cam etc
My current 383 will bout all parts the same (save for a cam with 10 deg more duration less lift and lazier ramps would make my old 350 look like a 6 cyl serious.

 

If time frame and a budget really aren't a concern the next thing I would look at would be how much power are you looking to make?
A 5.3 can be safely bored out to a 6.0L without the extra $1000 in a core, so CI wouldn't be a concern there and the bottom end stock parts make 6-700 hp reliably. An LS is more economical on fuel if it is something you drive frequently as well.
On the other hand the sbc is old school muscle and probably fits the car better but will not push more that 500 in a stock block reliably (over long periods of time, at some point it will break the block.)

 

Are you selling the 383 as a long block or just the short block?