Wow! But do they live winding them to 8k? I was so dead set on an LS a while ago, until a friend of mine put together what we call "The Engine Masters Special"- 598 blueprint shortblock with a Brodix top end kit and a decent hydraulic roller cam. That thing is so much fun on the street with its massive torque curve, but it is dead at 5700 rpm. That engine got me thinking a lot about the different combinations.

Would looking for an aluminum block LS be a waste of time to save another 60lbs or so? Are they as strong as an iron block LM7 or LQ4?

 

Energy mfg billet block is only 85 lbs... how far down the rabbit hole do you want to get?

 

I'm sure that block is pretty $$$... Maybe I wasn't clear, does the factory aluminum LS block have any strength advantage/disadvantage? I know they bring about $1k more around here.

 

I personaly do not find the AL block to be worth the extra money for a fun, strait line street car. From a strength /durability standard, guys have made stupid power with both.

 

Dumping big dollar rotating assemblies in a factory block makes little sense IMO. The Factory gen 4 rotating assy has proven to be roughly as strong as the factory block. So replacing one without the other doesn’t gain you much. IMO if you are shooting for 900-1000 crank stick with a factory long block. If you want much more than that or have a relatively heavy chassis... go with an aftermarket block. Or just go BBC as it will be cheaper.

 

Why not keep a Pontiac in the car?

 

I'll semi agree with this, If you keep boost low at peak torque, you're fine, but I know of more than a few that have bent the gen 4's especially on the 6.0's. Matt Happel bent some in his 6.0 with the VS 480 when he was pushing towards his 1k whp goal, and BMR here has bent them as well. If pushing the stock stuff make your hp at 4k and higher, and keep timing in check. The other thing to be said is, if you build a jy engine, you get a jy engine. If you put a few good parts in it, it may not make any more hp, but there's an advantage in durability. Even well tuned engines wreck parts when pushed hard enough.

 

The key words to me here are "pump gas." A mountain motor with boost is going to run a # easier on pump than an LS probably. In terms of assembly of a setup that's more mature EFI wise, the LS stuff wins hands down; You don't end up retrofitting an engine. That said, it's really really hard to go wrong with either truthfully.

 

Yeah, if I was going to do this budget and actually kind of build things I'd end up with a set of LSA rods and decent pistons. A set of Eagles isn't too many more dollars than the LSAs though truthfully.

 

Here is where I am at. NO progress with the car (still working on employment since I retired), but I am ordering a pre-bent 8pt cage from Chris Alstons at Christmas. I am going to go with a BBC. That's simply where my heart is. LS is a cool and very durable platform, but I love big block chevrolets. I have been looking for a suitable platform to start a build from, and I am not being too picky- MK IV up to the last Gen VI blocks. Around here if they are in decent shape guys want a fortune for them. I have thought about ordering a shortblock from CNC Morotsports, LJMS camshaft nice top end etc, but the price goes up very quickly. I have seen a 496" longblock from Blueprint Engines that is setup for "power adders" for about $8K, and has a warranty..... I dunno, it seems like the easy button but it kind of makes sense to me. Thoughts?

https://blueprintengines.com/products/496-ci-stroker-crate-engine-big-block-gm-longblock-bp49610ct

 

Is this your first turbo build? If so I would skip the fancy high end engine for now, stick in something basic to learn on that you don't mind tearing up. You can make a lot of power on a stock bbc with a turbo... enough to find all your chassis and drivetrain weaknesses. Then after a while when you are ready to go bigger do so. There are going to be a lot of "learning opportunities" and it would suck to run out of funds or maim a nice new engine. I mean, an engine swap takes less than a day, and a used BBC cant cost much to get started with. There are at least 6 on craigslist in my area now.

Or just order a crate engine and then you don't have to deal with oil leaks or ugly stock parts. My biggest problem with spending big on a motor for a project like this is that you will always be afraid of hurting it, you will never want to push the limits or experiment and that just sounds boring.

 

WOW, that makes a lot of sense! This is my first gasoline turbo engine, and I would hate to destroy a 10K longblock due to inexperience. This is why I ask questions. Thanks!

 

Didn't see that you'd updated. Honestly, look for 396 builds here. If you're planning on a short deck engine, I think you'd actually be surprised what some people have made on basically a stock one. Blownshovel comes to mind as does this build:

https://www.theturboforums.com/threads/big-block-version-of-the-grenade-dyno-s.332255/

 

Like others have said, you don't need a big budget engine to make hp with a bbc. Run whatever cid you can find cheap. Clean up a set of oval ports, or buy a budget head, and some good pistons/rods if you choose, and throw some boost and decent fuel at it. The stock bottom ends (even the 2 bolts) are quite stout, and will take some abuse. As usual, the rods, and pistons are the weak pieces.

 

I just found a crate 502 HO https://www.chevrolet.com/performance/crate-engines/big-block-502-ho used on CL, guy states only 500 miles on the engine, and is asking 4K. These have factory 4 bolt block, steel crank, rods and forged pistons around 8.75:1 compression, and 325cc iron rec port heads. The reason this caught my eye, I have gone and looked at 5 different big blocks around here, and they all have problems ranging from no oil pressure, no compression in at least one hole, already taken .060" over etc. Bottom line, used BBC's around here in good condition are like hen's teeth.

The 502 isn't a super high buck engine, but from what I have been looking at around here, if I have to rebuild it, I'll have at least $2500 in parts, plus machine work, and if I go that far, might as well get some decent heads etc... It snowballs quickly. Thoughts?

 

This is where the more modern ls wins... So many good used engines, and parts to choose from. The BBC is dated, and non aftermarket parts are getting tougher to find, especially something that hasn't been abused. The 502 doesn't sound like a bad piece if it's as fresh as he says.

 

Gen V and Gen VI BBC engine blocks typically have thin cylinder walls. They flex when you throw some cylinder pressure at them. You'll give up some ring seal and experience more rapid wear in the bore, piston ring, and piston skirt with a Gen V/Gen VI engine block when used at high cylinder pressure. Personally, I wouldn't buy a Gen V / Gen VI engine with the idea that I'm going to possibly rebuild it later and really lean on it. I'd only go that direction if the price was right, the engine could be used as-is, and I was going into it knowing that I was using that engine as a placeholder for a stronger build using a different engine block in the future. In many cases, you're better off with a .060-over Mark IV block if you're forced to choose between that and a Gen V/Gen VI, as there's quite a few Mark IV blocks that will have plenty of cylinder wall thickness at .070", .100", or even .125" in some cases; all of which happen to be oversizes that the aftermarket provides shelf pistons for.

 

The 400 that is in the car is the dreaded 557 casting from the late 70's where they tried to lighten it making it a little flimsy.

 

'67-'69 blocks are still out there. Marty Palbykin made 1600 HP and 1450 ft./lbs. of torque on a '67 block and a set of OE cast iron heads (I forget which casting number at the moment... I want to say they were 62's). Granted, both the block and heads received relatively extensive modification, but when it's all said and done the overall foundation was still regular old GM cast iron.

I'm not much of a purist when it comes to just about anything, but the last thing I'd ever do is stuff a Chevrolet-based engine in a Pontiac chassis. For me, a Pontiac doesn't have to stay Pontiac powered, but Chevrolet power in a Pontiac will always be sacrilege. Of course, that's just my personal preference. I realize plenty of people do it and are very happy with their vehicles.

I would be totally confident in a '67-'69 block, main studs, oversize main cap dowel pins, Arma Steel or 'N' crankshaft, H-beam rods, and a set of SRP or Icon shelf pistons up into the 800-900 FWHP range.

This wouldn't be a budget-breaking build, either. Stick with a flat tappet camshaft to keep costs down, avoid extra stress on the lifter bores, and not have to deal with fitting a lifter bore brace. A set of 62's, 16's, 670's, 96's (d-port), or 6X's would get you there without exotic modifications when coupled with boost. If the budget allowed for a set of E-heads or KRE's, even better. Port match a Torker II or Victor intake, slap on a CSU carb, and add an S475. You'd have an authentic Pontiac that made some serious steam and that could be driven anytime, anywhere, all without spending a ridiculous sum of money (provided you could do most of the work yourself).

 

Do yourself a huge favor and read yourself "how long till it grenades"
trb355's build & blown385's build on his supercharged to turbo sbc, both builds are mind blowing, & super informative.

I also vote for the super simple BBC build, built with enough turbo to handle 1000+hp. Ditch the pump gas idea till you get a handle on the tuneup. Pump e85 is your best friend! I'd say a good multi port efi system like the Holley hp/dom would be smart to do right from the get go! Also, overkill your fuel system so you don't gotta buy it twice.

Just speaking from experience I've bought 4 diff turbos, injectors twice, multiple converters, etc.. doing it over n over adds up. Try to make the best choice from the beginning.. & read read read