Looking at a fresh unassembled LT1 block.

Can the early 90's LT1 blocks be used to build up a multiport FI 350? In other words, are there any major differences that would stop me from bolting on all of the late 80's era TPI style parts onto the LT1 block? I would want to run a standard distributor (no opti), belt driven water pump, probably vortec or world products heads. I just dont know if theres anything about the LT1 block that would be incompatible.

Thanks!

 

To be clear I would be using the LT1 crank, rods, pistons, and balancer/pulley. I would be buying the cam / heads / intake. Would want to retain the multiport EFI so I can use my 89 PCM and wiring.

 

The cooling system is different on a LT1. It's reverse flow. You can't bolt on Gen 1 small block ( non-LT1) water pump, heads, and manifold to a LT1 block.

You either go all LT1 parts, or you get a Gen 1 block.

 

Definitely don't want the opti nonsense, so back to the drawing board then

Thanks.

 

You be better off with an L31 if you can source a TPI base,24lb inj, Alex spring kit, LT4 hotcam, and chip to make it work. Would be very strong!

 

Myself I think it's a great idea. LT1 heads flow as well as Vortec heads and are aluminum. The LT1 intakes only need an accurate distributor hole drilled to convert to standard distributor. With just an GM LT4 "Hot Cam" your near 400hp or better.

I really don't know why more TPI cars aren't converted to LT1. Third Gen Org has a reputation for using the intake conversion but I don't know why many whole LT1 swaps aren't done?

I can go to the local pick a part junkyard and find half dozen LT1's for under $200. Most are iron head motors but some are aluminum head motors for same price. BTW the iron LT1 heads flow better than the aluminum LT1 heads.

I say go for it.

 

First, the LT1 is a mutli-port injected engine. The runners are a LOT shorter than the TPI runners for a specific reason. The Super-Ram was all about that. The Stealth Ram, Miniram, and Edelbrock Pro-Flo, and other LT1 clone intakes were popular for a reason - No long tubes.

Second, LT1 heads are the basis for Vortec heads. The Vortec castings are designed for conventional coolant flow, and that it the only basic difference.

Third, there are almost as many cast iron LT1 heads as aluminum heads. There were about 309,000 aluminum headed Y- and F-bodied LT1s made before the LS engine came about. There were about 210,000 Caprice, SEO and Impala vehicles produced with iron heads from 1994-96.

And cardo0 is correct - Stock iron LT1 heads flow better than stock aluminum, and can be ported to flow better than aluminums. Stock iron heads can be opened up to 194CC runners on the intake side (from 170-ish) and to almost 80cc on the restrictive exhaust side.

It's far easier to increase valve sizes in iron as well, which really tips the balance in favor of iron, which is yet another reason for the popularity of the Vortec head swap.

IMO, if you want to keep it stock, keep it stock. If you want it to LOOK stock, close the hood. You'd be better off with the LT1 and eliminate the long runners. You'd be even better off with the LS6,

 

The major difference in the block is the completely different timing cover, balancer, water pump pattern, and the deck drilling for the reverse-flow cooling heads.

 

Glad you noticed this. Recently got my LT1 heads back from the shop and my larger 2.00" intake valves are past the flat of the deck surface just a tiny bit. Not very much but I will have to notch my plexiglass to measure the volume since it can't sit flat as is. Shop did shave the heads 0.010" though and I'm sure that's what did it. I had ordered flat milled 0.030" but I can see why they would have stopped at 0.010".. Not such a big deal but I try to avoid any sharp edges in the combustion chamber.

Something I do regret is not polishing the chamber while the stock small valves were still in. Man those chambers are rough with all the carbon cleaned out.

So my last visit to local Pick a Part there was a clean LT1 intake laying on the ground in front of a caprice. It was so clean and looking it over several times couldn't find a thing wrong with it. Had to pick it up for like 30 bucks as a spare. Have at least 2 spares now. First one I got for $40 included all the injectors and rails. But again for a third Gen you want to drill for a rear distributor and use the stock third gen injectors w/ECM.

 

Thanks everyone

I was super close to pulling the trigger on a Jegs L31 ($1850) with the associated conversion parts (intake etc). But I didn't. I was looking at about $4000 all said and done with headers, programmable computer, etc. I decided it was too much to put into a Sunday cruiser.

Found a really clean freshly machined LT1 short block with intake, water pump, crank, rods, pistons, just no heads basically, about $300. I was thinking I could finish that off for under maybe $2k total but didn't know the LT1 block was a different animal.

Also thinking I might just look for a cheap L98 core to strip and rebuild, maybe stroke it out to 383.

No real rush, car runs good as is, although I think I spotted a little rear main drip recently (I get a drop or 2 on the floor in that spot now, ever since I had the torque converter cover off since I lost the screws to put it back on lol.....)

I also kinda want to paint the car, it was red from the factory, someone painted it black, and it's a sweet 10-footer but the inner trunk, engine bay, under the tonneau, behind the tails, etc, is still red. At least they hit the door jambs with the black..... I got quoted by a local guy $3500 to respray it back to red inside and out. Body is nice so that helps.

I'm into this car right now for about $6k, which includes the purchase, new dash pad, transmission rebuild, and other odds and ends. I don't want to go overboard, I an trying to not put a lot more $$ into it, if any, than it could ultimately be worth. 80K miles and overall it's a survivor, so I think with a careful partial resto she might be worth around $12-$15k depending on how clean I get her.

Decisions, decisions......

 

 

Nice looking camaro. Worth a $10,000 driveline I'd say. You can't buy these cars new anymore and most that still running are very ruff.

 

Thank you.

And yeah, I don't want to put $10k total in the entire car, let alone in the drivetrain alone Bought it for $5k last fall, I would like to keep the total investment under $10k while cleaning it up and refreshing the driveline a bit. Not going to be an LS swap here in the near future......

 

Your philosophy seems rational. Keep it running well, pick up a spare and start building what you want on your schedule. When ready, do the swap.

The LT1 internals should fit into an earlier block, and the PM rods and balanced crank are superior to the older stock 1-piece RMS rotating assemblies. The problem is the difference in the key for the crank for the balancer. The old style key may have to be filed short if a stock LT1 type timing set is used depending upon the year of the LT1 assembly - There were 3 types.