nwav8tor

Can you tell that I'm a novice? What would it take to have my base '71 350 270hp converted to a LT-1 300-330hp motor? I assume it'd at least need different heads and maybe intake & carb (Holley?). Would different cam and pistons be required also?

thanks,
Paul

530planeman

Paul
LT 1 uses an high rise intake so would need big block hood or LT 1 hood ,also TI dist and module, pistons ,cam, holly carb .4 bolt 010 block .Might be cheaper to just buy an LT 1 $4 to 5 k
There is one in Dubuke Ill. for $2500 on Craigs list under Chicago.
Hope this helps
Wes

Easy Mike

The LT-1 is well documented. The How To Hot Rod Your Smallblock Chevrolet books are likely to have a list of LT-1 stock parts. Purchase the parts; assemble the engine.

Tom73

Paul, what are you wanting to do? Do you want an LT-1 clone or are you just looking for more HP? For a clone you will need a lot of very specific parts. For more HP there are lots of options.

Tom...

GaToy

I want to get rid of the LT1 out of my '95 impala to make room for an LS3. A lot of the Impalas and caprices ditch the LT1's in favor of LS motors.

Tom73

That is a different LT1. That was a filler engine between the classic Chevy Small Block and the new LS series engines.

Easy Mike

Yep. An LT-1 is not an LT1.

nwav8tor

Thanks for the replies guys

I didn't know it was THAT involved. Possibly more than I want to face

For me it'd be purchase the parts; have someone else who knows what they're doing assemble the engine!

I'm in the early stages of a resto and was contemplating an LT-1 upgrade, but didn't know it'd be so involved. Will probably keep what I have with some tweaks for a bit more power. The sound is probably more important to me anyway...

Thanks for that info, I'd always wondered about the two different types of LT engines. Didn't notice the LT-1 vs LT1 difference

keithinspace

To build on Mr. 530planeman's comments, I can absolutely tell you that it would probably be cheaper and less aggravating to build a 500+ HP small block stroker engine than it would be to build something that mimics a 'true' LT-1 engine.

I JUST got done rebuilding my NOM LT-1 into a fire breathing monster.

--I kept the 4-bolt block. Easy enough. If you don't have one, get one.

--I kept the forged crank. You'd have to buy an Eagle Forged crank...at that point, you may as well think about building a stroker.

--I kept the TRW mini-dome forged pistons. Again...tough to get these exact pistons. More cost effective to not be restricted by the "LT-1" aspect of the build.

--You'd pay the same for a new set of forged rods as to have an old set of forged 'pink' rods rebuilt. Ask me how I know...I now have Eagle rods in my engine with the better oversized ARP cap bolts.

--To pay to purchase and rebuild a set of camel hump heads, you can get a very nice set of aluminum heads custom built to your specifications. Ask me how I know.

--I personally would not put a flat tappet solid lifter engine in the car. Once you're in this deep, it makes no sense to not go with the stability and durability of a roller setup, even if you stick with solid lifters. I did and it is awesome.

--If you put solid rollers in, there's absolutely no reason not to also install a Rev Kit.

--You'll pay the same (or less) for an Edelbrock Air Gap intake as you will for the proper Winter's Forged intake. And you'll gain at least 20 hp (probably more) in the exchange. Ask me how I know.

--An MSD ignition setup is just a modern, hella adjustable version of the TI setup. And you'll pay more for a numbered TI setup. Ask me how I know.

--Top it with a Holley, which is fine. I topped mine with a QuickFuel annular booster double pump and there is no way I could be any happier with the choice.

--No reason not to go with a Schuman oil pump.

--No reason not to go with a Cloyes timing chain setup.

--No reason not to get a good quality roller shaft style rocker with polylocks. The LT-1 came with 'normal' stamped rockers. I can tell you: It's freaking tough to keep those things in adjustment. Ask me how I know.

--No reason not to go with 7/16" rocker studs instead of 3/8". Doesn't cost much more and adds GREATLY to the dimensional stability of the valvetrain.

The list goes on. I think you get the point. For each and every one of the decisions you'll face, there will be an alternative to the TRUE LT-1 parts that will both outperform AND be similar price or less expensive.

Absolutely not bashing the LT-1. That was a true race engine for the street. Awesome piece. I drove a summer on mine before tearing it apart for many well-justified reasons. Fun engine.

But I like my 'new' engine better. I've not put the car on a dyno, but I can say with absolute confidence that I'm at/above 450 hp at the crank. I may be knocking on the door of 500 hp, but I won't say that's what I have until I can prove it.

As an aside, I personally wouldn't embark on ANY of this until you have an engine builder you have a relationship with. Not a machine shop or an engine 'assembler'...a BUILDER that understands the nuances of constructing a high-performance one-off engine.

Best of luck to you!!!! Sounds like fun!

nwav8tor

Thanks for the insights from your own experiences! I'm not looking for a fire-breathing beast, just a great running machine with a bit more horses and a sound that really wets your whistle. I'm starting to head out to local shows and events to get info and recommendations for engine builders. I want a game plan for the engine before I start considering options for drive train and suspension. Going for mostly stock look with mildly upgraded components for durability and ride improvements.

Paul

LS4 PILOT

The parts list including block is very different from an L 48 , pistons , four bolt mains, forged crank , special oil pan, mechanical cam, on and on.

If your going to keep the block and stay vintage ....I think the direction to take your Hydraulic cam L48 is to use L46 parts , the old 350 / 350 HP motor cam , exhaust , heads , cam , pistons . ....you sound more like a hydraulic cam person than a mechanical lifter cam person. The L46 for 1969 was quite a performer . I used the hi compression heads from a 327 /350!and pistons to make a nice a nice up grade with te 350 hp cam back in the 70 s. Recurve dist. ....it ran very strong with it's two bolt main block. The L46 used a Quadajet too, like yours too! And the same intake you already have.

Of course there is a million better modern motors nowadays ., roller rockers , etc.. Mine was all GM parts from over the counter head off a corvette race car.

nwav8tor

LOTS of stuff to discuss with my yet to be found engine builder!!

Thanks,
P

Gordonm

Have you thought about a crate engine? There is a variety of different power levels and it is one stop shopping with all the matching parts. I have built many motors and installed a bunch of crate motors also. The crate ones are quick and easy.

nwav8tor

Yes Gordon, I have thought of the crate route. I originally wanted to keep it original as much as possible, but now am not as concerned with that as I used to be. If my block checks out OK I guess I'll have to add that into my cost/benefit analysis. If the block is bad (shouldn't be since it was running fine when it was parked 26 years ago) the crate engine will no doubt be a good viable option.

Paul

leadfoot4

True, but the LT1 that you're talking about, is NOT the same LT-1 that the OP is talking about....

softwarejanitor

Buy a crate motor of the power level you want and have it installed. Have your original engine prepared for storage (add corrosion preventative lubes to it and package it up to keep dust/dirt/rodents/bugs out). Enjoy your car with more power and keep your original engine for value, you can include it if you ever sell the car.

Are you saying your car was sitting for 26 years???

Gordonm

set the original aside. Just did this for a forum member and he could not be happier. He went with a 420 HP roller cam 383 and then I installed a 700R4 trans and the car is awesome to drive. Much more fun.

I have another one to do also. Installing a ZZ4 with a hot cam and a TKO 5 speed in a 69 that has a stock motor and a turbo 350 trans in it now. Quite boring to drive this way.

nwav8tor

Yup, that's the case. Sat in a barn's shed for 22 years and was in my garage for 4 more as I prepped the garage for the restoration project. Engine wasn't stored properly, so I don't want to run it at all before it's rebuilt. If I do go the with the crate engine, I think I'll leave the original one as is and let the next owner deal with it as he or she sees fit.

P

softwarejanitor

Yeah, those swaps are night and day differences. The engines obviously make more power, but it is pretty amazing how much difference a TH700R4 makes over a TH350... lower low gear and the OD 4th gear makes cruising much smoother. The 5 speed all the much better of course.

softwarejanitor

My 1980 sat in my garage for about 10 years before I got it running again. It cost me a bunch of $$$ with all the little things it needed. I hope your luck is better than mine. I could have easily bought another car for about what the work and parts cost...

I agree with not messing with the original other than I'd do some better storage of it... pull the plugs and shoot some oil in each cylinder and goober all the bare metal surfaces with some cosmoline (or chassis grease), etc., then wrap it in plastic and cover over any openings that critters and dust can get in.