LT1 in a shoebox?

[five7kid]

I have long dreamt of a Ram Jet 502 for the '57, but at around $10k, that's probably a long way off. It would be, though, a simple way of having 500 HP and EFI under the hood. I was poking around eBay recently, saw several LT1's available, have been considering one for the Camaro, but then it got me to thinking about potential for the old girl.

Now, how would an LT1 compete with the 502? Probably not very well NA, but it should be able to keep up with the current 396. This is what I was thinking: LT1 set-up (whether Vette, f-body, or b-body would dictate what else is done). First step would be to stroke it to 383. Then, either ported or LT4 heads (if the engine is b-body, then new heads for sure - or not?). A good cam, other typical LTx go-fast goodies, etc. Build it forged, it could be sprayed to get that 500 HP. I'd like to replace the TH400 with an OD tranny, already have a TH700R-4 that I could build up, but a 4L80E would be peaches, I think. 4.56 gears should get it out of the hole with authority, OD would keep it road-worthy.

All this should be a good 100 pounds lighter than the 396 (not totally sure about the 502 weight), tuneable EFI, good for street & strip.

To be sure, this project isn't going to be started this winter, but I could start gathering parts anytime. Is there anything about this approach that sounds off-base to you?

[mrcadillac]

There's a guymaking 500hp with a B-body LT1's with ported F-body heads, on stock bottom ends!(fried one) Plus, his cam is only a 224* intake duration at .050. With the 700r4's first gear of 3.06, 4.10's get you moving plenty, and keep you from going into over drive, or past 6000rpm at the big end. If your wondering how fast these Tanks go... take a look at this. It might suprise you how fast guys are going on the stock bottom end... then add JUICE! http://dan.esteban.com/impalass/ReturnTopET.asp?Sort=Class&SelectedClass=6

the only thing that is off base, is the need for LT4 heads... The Aluminum LT1 heads are pretty killer once you give them to a porter like Llyod Elliot, Advanced Induction, Port Pros, etc... Even under 396 strokers, these guys have shown there heads can flow. AI even does so with very small inlet runners. I think there "big" heads are only 190cc. which are what the guy I was talking about uses. Right now there is a war on who can get the deepest into the 11's, NA on a stock bottom end... some of the guys even run at weights of 4300lbs!! WOW!!

[five7kid]

That's quite a list.

I would prefer to stay NA. Something about stopping off at the dentist's office to go fast doesn't really appeal. I might consider turbo or SC, though.

What about iron vs. Al heads? I've heard conflicting stories. If the engine happened to be from a B-body (because that seems to be more available these days), I assumed that would be the more justification for replacing the heads. If replacing the heads anyway, why not go with LT4?

Also not completely clear on 383 vs. 396. For Gen I SBC's, 383 seems to be the more common limit. But, for Gen II & III, more seem to be going with 396 or bigger. I figured 383 would be simpler, and not sure how much difference the extra 13 cubes would make for the expense.

I see a lot of the guys stuck with 4L60E's. Since that's basically an electric TH700R-4, it's encouraging to see the power can be handled. The 4L80E would take the power with less stress, and has a lower # 1st gear - hence the 4.56's instead of 4.10. But, you're right, with the TH700, 4.10's would get it out of the hole fine.

[Zupercharged28]

i think with the 4.10's, and a 383 lt1 with a good H/C setup (forged rotating if you wanted) you would be out of that hole EXTREMELY fast.a well build, blueprinted, and quality 383 lt1 should make right around 420-450 NA. that would be nice for the money, no? and as long as you have a decent stall and some trans work you should be set! the 700r4 and 4l60e s are stronger than you think! you wont need a 4l80e that way over kill. i just had my 4l60e rebuilt with all red eagle stuff, new boost valves, new clutch pack etc blah blah bla shift kit blah and stuck a 3200-3800 stall on her and she gets out of the hole a little TOOO fast for me. and thats just a regular 350 ci lt1 with a procharger!

[five7kid]

With the current set-up, the '57 cuts 1.75 60' at sea level (about 1.83-1.85 at altitude). The LT1 would weigh less than the big block, so with similar displacement it should pull out about the same.

There is a fellow racer out here who has a '57 Nomad with Gen I 383, TH350 w/4000 stall, 4.88 gears, who runs about half a second faster than I do - but my 60' is about .15 quicker than his. Weird. The Nomad weighs a little more than my sedan, though. He traps at about 6800 RPMs, which doesn't seem to bother the engine at all. He's running Dart heads & single plane intake, I forget the CR but he runs race gas. Hydraulic flat-tappet cam. Doesn't drive it on the street like I do.

His set-up was more reason for me to consider the 383 LT1. I didn't think high trap RPMs would be a problem with proper bottom-end build and valve train.

Back to the Fe vs. Al heads - I've heard ported iron heads will run with ported aluminum - true, or does it depend upon the level of porting? I'm also not clear on the differences between LT1 and LT4 heads and intake.

[mrcadillac]

the LT4 heads have more meat for porting. same as the manifold. Iron heads actually flow better than early Al heads, and the same as later ones. Ported irons can be taken ALMOST as far as the early Al heads can. but most go Al heads as the Irons tend to cost more to port, ship, weigh more. The early casting Al LT1 heads have been proven to be fantastic even on strokers. Places like advanced induction, really make them scream.

there are differnt classes on that list. and there are some FAST stock bottom end cars NA. many that are faster than aftermarket headed 383's, that are on boost! and many of the 383's are NOT cheaply built ones. The boosted Impala specially I am talking about, the guy also has a 502 powered Impala, and a NA 383 Impala.

some of those guys who have stock bottom ends, NA, with killer heads are runing 1.6** 60'.... Very impressive. I donno what a shoebox weighs, but if it's around 4300lbs, you can be doing the same(at sealevel)