BOD1979

iTrader: (1)

I am looking at changing my engine. Looking for around 600hp.Should I put a 496bbc or a 408 LS motor. Don't know much about the LS. Want to put a tremec 6 speed behind it. Would the LS be a lot more money because of the adaptors. It would be mostly a street car with the occasional auto cross

Orr89RocZ

iTrader: (20)

Probably can get 600 hp easier with a 496 and maybe cheaper but a good 408 ls can do 600 without much effort either. Tough call. 496 likely would be a touch heavier but have more torque due to superior cubes. Really need to price things out and see what you can get for the money. Ls you can easily find a T56 and hold that power

Blade09

Not sure I would ever want to autoX a big block car, seems like it would turn like crap. But I have heard that with a set of aluminum heads and tubular K member you can compensate for the increase in weight but I've never been able to afford such parts to compare lol.

89rs454

I would get an LT1 With the right parts 550-600 crank hp could be achieved and way lighter then a bbc.

572_Rat

I just put a BBC in my Camaro, I am a BBC guy all the way but after putting in this car an LS motor would have been a lot easier. You can get tubular k-members with LS motor mount, and with the LS motor you would not have some of the fitment issues as you do with a BBC

1gary

Much depends on where you want the power curve. Certainly the BBC in lower rpm's overshadows the LSx. Posted a report in the LSx section about how the LSx's have been having lifter failures and need to be treated the same way as a flat tappet cam with Gibbs or Brad Penn oil.

Jonesyfxr

iTrader: (2)

I'm a BBC guy too. I'm putting one in my 79, but it's a street/strip car. I'd stay away from a BBC in an auto cross car, you'll have TONS more weight and it'll most likely push in the turns....BAD!

The LS engine is available from almost any bone yard. Even an LS1 would be a great starting point. Just remember with that much power you'd better stiffen up that chassis with every possible support you can find, build or buy.

Good luck and keep us posted!

No4Play

good luck getting 600rw out of a BBC or an ls1/2/3 with out going extreme N/A or boost/nitrous. My ls7 in my ZO6 makes 580rwhp and 560rwtq. Thats 427ci, 10 hours of hand porting and polishing on stock ls7 heads, upgraded springs and exhaust valves, 246/256 cam @ .650 lift 112 lsa, full bolt ons. First time out, car ran 7.25sec 1/8th @ 91mph, 1.27 60ft on bald drag radials. easily mid 6's with more seat time and better tires. I could mill the heads .030 and make 600rw but it would run hot and be a pain in traffic.

We built an LS2 vette that made 480rw through a 6spd auto. It was a stock ls2 short block with LS3 heads and intake, custom grind cam from comp and a tune. Car was insane.

I think a 383 ls1 with a tad bit higher compression ratio and a fairly good size cam will make a **** ton of torque and be plenty for a a 3rd gen. ported and polished 243 heads or a set of decent flowing trick flow heads would make that thing sing. My build in my sig isn't finished yet but when it is which should be this week, I'll post up some numbers.

Orr89RocZ

iTrader: (20)

I dont think he was refering to rear wheel hp but a bigger inch bbc has a much better chance at that power than any ls with factory style heads imo. You build a 496-540" bbc and 700-800 pump gas hp is acheivable.

And your times dont jive. 1.27 60 ft is incredibly fast yet only ran 7.25 at 91? What happened on top end? A car that can go 1.2's 60 ft usually is well over 105 mph 1/8 mile. My 500-550whp nitrous car went 1.41 and 6.8, 103 mph. 400 whp all motor trapped 93. A z06 at 580 would be over 100 mph and doubt it could ever get a 1.27 60 ft

No4Play

This is true and I wasn't sure if he was looking for a streetable build or a strip car...hence my suggestion.

I'm telling you what the car ran...its a 6sp car. stock gear, full weight. I did fat finger the 60ft. It should have been 1.37 60ft, 7.25@ 91mph. but now that you mention it, that trap speed does seem way low. but that's what I'm recalling from the time slip....it was at redline raceway in caddo mills, Texas. I'm deployed at the moment but when I get home I'll double check the slip. It was my first time taking the car to a track since I did the work to it.

Orr89RocZ

iTrader: (20)

That launch is incredible for a vette on radials, you run 17" tires for brakes right? What radial you on? Mickey? Hoosier?

Figure out whats goin on in the top end, you have the launch figured out thats for sure. Car will be a monster

No4Play

I'm recalling this from memory, but I'm sure it was a 1.3X 60ft. I will find the video that was posted on facebook and try to post it here. All I have was the incar from my go pro. I run CCW Classic 17"x10.5" on some bald *** hoosiers. Don't remember what size as I bought the wheels with the tires on there and just slapped them on and made some passes. first 6 passes were 8.xx and my last 2 were a 7.4X and fastest pass of a 7.25. The difference was dumping the clutch the first 5 then learning that I needed to slip it on the last 3.

Sorry to hijack.

572_Rat

[quote=No4Play;5648336]good luck getting 600rw out of a BBC or an ls1/2/3 with out going extreme N/A or boost/nitrous.quote]

Do you know how easy it is to make that kind of power with a BBC. Power and torque with a BBC have never been a big challenge, my BBC was dynoed at 900hp on 91 octance pump gas, this is a street motor,nothing exotic and is N/A

No4Play

Its easy to make the power with a BBC but you don't consider that to be a bit extreme for a street car? I mean there is a difference between driving it on the street and being streetable. Hell I can pull my trailer car and drive it on the street. It would **** me off to build a pump gas 600+rwhp big block to drive on the street and watch the gas gauge drop, lol. Maybe it that's just my opinion...sorry for posting.

Atilla the Fun

Here's where a pair of really small turbos on any stock LSx with a loose-convertered automatic, possibly with a semi-manual valve-body or an electronic version with paddle-shift, would be the best option. Sure, the turbos would be maxed out at 700 HP crank = 600 HP rear-wheels, but they'd stay spooled when competing, yet you could still be running an all-aluminum small-block that can do 30 MPG with that loose converter locked-up. As always, build for driveability, then if power is lacking add boost. Sure, AFR 315s on a 496 can make the power, but you'll never see 20 MPG, and it'll never pass any future emissions tests which are coming.