Just finished my first build (heads and cam)on my car so now I'm looking to,do another one..

Never done an entire motor before but I'm kinda looking to do a Nitrous 370 or 408.. I just ran across a 5.3 block locally for 25$! Is there any disadvantages to getting a small block like this bored to those cubes? I really have no idea if its even possible, just trying to get some insight on what is possible with this block.. Guess my question is will it effect cam size, stroke, any of these things?? Enlighten me please.

 

You can bore the 5.3 out to Ls1 size. To get to a 4 inch plus bore you will have to sleeve it.

 

Bore it to a 3.903 - 3.905 and a 4" stroke crank and you'll have 383ci.

 

There are 2 5.3s, aluminum and Iron. Iron is preferred for boring to 3.903/05 but it can be done with alum.

 

So, not going to be able to go to the 408 with this one i don't guess??what about cam sizes, clearances and what not? I will probably never be able to afford a fI build, thats why it'll probably be monster cam, big heads motor.

Predator..th never asked the guy if it was iron or aluminum. He did say lm7, I assumed it was iron?? Would either block be better for my goals?

 

Does the 383 rotating assemblies compare close in price to the 370/408 packages?

 

Lm7 is iron

 

Yes it's about the same. The crank and rods are very similar (4" stroke, 6.125 rod length) while the pistons are the only real difference (4.03 vs. 3.903).

But whether it's a 4.03 off the shelf piston or 3.903 off the shelf piston doesn't matter, they are the same in price. So overall, a 383 stroker kit is about the same as a 408 stroker kit.

The 370 is different as that uses a stock crank, so should save you some 6-800 bux over a stroker kit.

 

summit sells a ls1 iron block for 750 bux.. i think it would be cheaper to buy that then buy a used 5.3 then have it bored out/honed/new cam bearings.

 

ERL makes some really bad *** big cube engines out of the aluminum 5.3s. It seems like they said there was something that made it one of the strongest factory block available

 

Its on sale http://www.summitracing.com/parts/sum-150105/overview/

675 bucks

I have a ls1 crank,rods,pistons "that are to small" Can I use my crank and rods with new pistons with this block?

How about my 241 ls1 heads, would they work? and if so will my compression suffer?

I am new to ls engines, but cant wait to put one in my 78 Corvette.

 

if you're starting from scratch, try to find a bare 6.0 (LQ4 or LQ9) iron block. The cost to bore/hone the 5.3 block would be around $300, which would likely cover the cost of the 6.0 block - and you'll still have a smaller bore with the worked 5.3 block.

 

Ya, the steal on the 5.3 got gone before I could get to it. I probably will just keep my eyes open for the 6.0 block. After talking to the machinist, it's probably what I want to do..

 

Take this mans advice! I had a 6.0 390'' from AES built with callies forged internals and made 924/878 with my TT C5 Z06. I had zero issues with the car and it was very streetable. No heat issues anywhere. Coolant temps stay in the 200-210 range in dead heat of the summer with a stock 197* thermo. This was a budget build and would be a perfect start for you. 6.0's are great for any power adder bc they are iron and have thicker sidewalls to fight against rod angularity of a largely stroked rotating assembly. Hope this helps...Good luck!