dhirocz

I think I got it figured out so I'm gonna try it out. I'm taking a 400 sbc and boring it .030 over with a 4" stroke crank to make 434 cubes. 2 blocks of metal were already built up on either side of the front cam bearing, ground flush and drilled and tapped for a roller cam retainer plate. One more was done for the oil pump drive adapter. I built an adapter for the LT1 timing cover to fit to the front of an early small block and machined the face of the timing cover to make up the difference. I'm going to run 1" water pump spacers and an electric water pumpto make room for the opti, and the rotating assembly is going to be internally balanced so I can use an LT1 style damper. Heads will be ported 18 degree brodix heads so I can run standard valvetrain and exhaust, with a welded and ported LT1 intake modified to fit. 12:1 compression, splayed caps, hardblok, 58mm TB, and 42# SVO injectors. What do you guys think? Alot of the test fitting of components and the timing cover adapter has already been done. Any suggestions? I'm looking to come up with a bolt-in alternative for people who want to get big cubes for less out of their LT1 cars. I'd like the motor to rival that of the new Z06 without having to have a huge cam or spray. I'm open to comments or suggestions. I try to make or fabricate most things I'd want that the aftermarket doesn't offer.

Next...AWD!

Red95Formula

Why run a ported LT1 intake on a huge motor like that? I would think you need some kind of sheet metal intake to handle all the air to feed that beast. Wherever this goes good luck and I would like to see that thing complete.

89385formula

Yeah a 434Ci motor will take need much more than that intake can offer if you ask me. I would look into a converted single plain, or a sheetmetal intake as well.

dhirocz

I'm just looking into making it as much of a bolt-in affair as possible. The intake will be fully worked, cut open, welded and ported, with the EGR passages removed. It'll still be marginal for a motor like that, but I'm trying to stay streetable...roughly the same driveability as my 224/230 had in my 350, maybe a little bigger. I'll make sure to modify the intake bolt pattern, not the heads so the single plane intake would bolt directly to the heads.

amean94ta

Its not a good idea. If you want to go injection do it but not with lt1 parts

whontime

Just looking over your post I see atleast two bad ideas.
1)Using a stock 400 block for a build like this
2)Using the LT1 intake for a 434 ci engine.

96SilverRam

I glad to see someone is trying to make the LT1 scenario work for big cube small-block

dhirocz

The whole idea for the build is streetable torque and power...lots of it. If the LT1 intake doesn't do it even welded and ported than another will come later. It's what's available right now. I'm already looking into single plane intakes though.

Start with another block other than a 400? Crazy. I dont have that kind of money, especially to be welding on the thing. I'm going to work out the kinks on a less expensive setup before getting carried away with spending money.

Part of the idea here is to have to motor look as much like an LT1 as possible and to use LT1 EFI parts.

whontime

You are going to be dumping a ton of money anyway. The factory 400 blocks aren't know to be the greatest item for big power anyway..some live, some don't. There is a good bit of expense to an aftermarket block, but it would be some nice insurance. Good luck regardless, I just think that thats a lot to ask of a stock block and a stock intake casting.

dhirocz

I have done several 400's as well as some people I know. Done right they hold up fine. U have to use a 2 bolt block since the 4 bolt blocks are actually weaker, splay the mains, and hardblok it before u clearance for the crank. Not overboring more then necessary is also a good idea.

If this works out fine, then I will most likely upgrade later on. I just want a street motor out of this that makes gobs of power in the midrange, not a max effort RPM motor, or else I wouldn't consider a factory casting. Of all the 400's I've seen, several were strokers, and only one came apart...but it wasn't a block related failure. When I get the kinks worked out and I'm confident that everything is running fine, I will consider a dart or equivalent block with a 4.2" bore and longer stroke to build an even bigger motor. I'll also step up from the LT1 intake to a single plane. For right now, the factory block and p/w intake will do unless I find a deal on an aftermarket block.

96SilverRam

You have peaked my curiosity on this 434 LT1 (400 block) buildup. Care to share what year 2 bolt 400 block a person would need to try and do something similar. Maybe you could post a detailed list of things your doing as you do the build. I would be very interested in knowing if I could do something similar with a 400 block and come up with 427 LT1. I'm assuming if the block was painted black there would be virtually no way to tell this is not a LT1 sitting in my engine bay ? What about all the fitment of intake, heads, timing cover (96-97 with CPS sensor) accessories to make it looks just like a LT1. Let me know

LT1TONY

I like your idea of trying to make a big cubed motor for less and using the LT1 intake.

Good luck and keep us posted on your build.

SStrokerAce

#1. the timing cover doesn't fit
#2. the waterpump doesn't fit
#3. any LT1 owner could tell it wasn't a LT1 pretty easily.

BTW if you really want to make a 434 LT1 you need to sleave all 8 holes to get the 4.155" bore.... any other way and it's just a SBC that you are screwing up with LT1 part IMHO.

Bret

dhirocz

1. I already figured out the timing cover issue. Like I stated above, I milled down the mating surface of the LT1 cover so I could fit an aluminum 'adapter' in between it and the block. Already bolted it on the block, fits perfectly.
2.Ditched the LT1 waterpump in place of a standard sbc electric water pump without a pulley, spaced off the block with a 1" adapter to make room for the opti. Also fits fine, but sucks to give up reverse flow cooling.
3.Since the engine is internally balanced, I can use an LT1 damper and accessories since I dont require a water pump pulley. The water pump is the only giveaway to the engine not being an LT1, that and the top of the water pump boss not being rectangular. Small details. That and the third freezeplug if the block was originally a 4 bolt.

LT1 type heads would require modifications to the deck surface, but since it's kind of a hybrid bastard child kind of motor, I decided to use standard SBC heads for more choices and just adapt the intake. Intakes are alot cheaper than heads so I figured that would be best.

I dont care if it's technically an LT1 or not, if it fits and runs fine without jerryrigging anything. So far all the adaptive work is top notch. If Dart made an aftermarket LT1 block, would it still be an LT1? Doesn't matter, as long as it runs the same. But they dont, which is why I'm doing this. That's why it's LT1 injected, but not an LT1, like it says in the title.

I already figured out all the details guys. Just comes down to getting the thing together now.

Mindgame

Why not just build a big gen1 FI smallblock? Why keep all the LT1 stuff and try and make it all work?

I've already done the big 1st gen thing and it wasn't terribly difficult. Just wondering why you're going this route.

-Mindgame