I have thought long and hard on this one. I am doing a engine buildup this winter. I plan on spending around 7500.00 dollars. I can go over or under no big deal. I will be going with a 383. The reason I ask this in Advanced Tech is because I want the correct answer. The LT1 block is a two bolt, we all know that. My question is if the block from another vehicle with a 4 bolt main and 2 peice rear main will be the same. I would like to do the the engine while I still can drive my car. If I can build any block, then I can have a 4 bolt main, and just switch the nessceary parts when I do the swap. I know the LT1 is a bit different at times, but will everything bolt up and work like it is suspose to on a non LT1 block? I have a engine builder at work who thinks it will, but I was hoping someone has tried this or looked into it before.

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Arrest ME Red 1994 Camaro Z28 Convertible
just a chip and a muffler, well maybe some headers
http://home.attbi.com/~mycamaro/

 

You'll need an LT1 specific block. However GM LT1 Crate motors along with LT4s have 4 Bolt Mains. Also any block can be converted to 4 Bolt, or Splayed 4 Bolt caps. That is if your application even really requires the 4 Bolt Mains.....

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Kurtis Tamez
LT4-396.com
97 Z28 LT4-396
94 Firehawk LT1-396
Team NW F-Body

 

What makes it different? Is the actual mount spots different? I'm just wondered. I know I will need the 4 bolt main, just no reason to build a bullet proof lower end and run it with 2 bolt caps. I was hoping to get out of having to have the splayed caps put in. Any idea on what a block is going for from Gm?

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Arrest ME Red 1994 Camaro Z28 Convertible
just a chip and a muffler, well maybe some headers
http://home.attbi.com/~mycamaro/

 

My block only has 2 bolt mains. Using ARP studs, you can make it as strong as a 4 bolt without weakening the cap mounting area.

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Stephen's racing page
or check out the race car

87 IROC SuperPro race car
461 big block
Best ET on a time slip: 11.589
Best MPH on a time slip: 115.91
Best corrected ET: 11.114

Altitude corrected rear wheel HP: 457
Best 60 foot: 1.646
Member of the Calgary Drag Racing Association

 

I agree. In most cases, a 4-bolt is unneccesary. I think a studded 2-bolt is good to the 700hp area in a small block.

The LT1 block is built for reverse cooling. The coolant passages, and I believe head bolts are in a different location then a gen 1 SBC. Just get a used bare LT1 block, and use ARP studs. You'll be fine.

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-Joe
79' Z28 4-spd
http://joesmith59.freeservers.com/
*Boycott Lapeer*

 

From what I understand, the flywheel will have to be changed since the bolt pattern is different on the crank snout. Then, the torque converter will be different, and the the tranny... etc...

Buy and LT-1 used, and put studs in everything. Splay it... Buy a 4 bolt LT-1 from a vette if you feel it's necessary. It will hold up.

-Shannon

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"Yep, getting drunk at the ol' flower shop"~ Homer Simpson
Http://nomad.cz28.com
Need to Buy stock Throttle Bodies...Email me
'95 White Z-28 T-Tops
Cold Air Intake, Ported MAF, Ported Heads, B&M shift firmer, !cat, !iat,!egr, Home Made MonoBlade, LT4 Hotcam, Cloyes, Taylor 8.5MM, Comp cams pro magnum rockers, Hooker Long Tubes, True Dual 3" exhaust, CSI Water pump, FastKitteN in the passenger seat

Best ET (Stock): 13.84

 

On a similar note is it nessecary to have the block aligned bored/honed when using studs vs. bolts?

I would think not since you would still be using the same main caps but what do I know?

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Jason
93 TA, M6

 

A number of points need to be clarified. An LT1/4 block has a number of characteristics that make it non-interchangable with a "traditional" SBC. The cooling passages are different, so different heads and intake are required. The distributor is front mounted, and if you want to use a SBC with a distributor it is difficult to fit one under the cowl of a 4th gen. The LT1 PCM needs signals from the Optispark, so you need to run one unless you go for an aftermarket ECU (or plan on using a carb setup).

There are no new LT1/4 blocks available from GM. I suppose some dealer may have some though. Most people feel it isn't worth the trouble to adapt a traditional SBC to fit a 4th gen. The only exception I can think of is an exotic race setup.

Rich Krause

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'95 Z-28 383 with Vortech, nitrous, etc.
"1FASTZ28"

 

You guys have been very helpful, I appreicate it a lot. I will probably end up finding a used block and having it machined. I understand what alot of people are saying about a 2 bolt being fine in most cases. But I am not totally sure how far I am going to take this. I have the 210cc AFR heads being prot matched to my lt4 intake now. The intake is being hogged out to compensate flow for the blower package I intend on putting on. I have not decided on which package to use, but I will have one. I want the ability to run big numbers. This car is just a toy anyway, so I want it to be a incredible toy. I am planning on a 9.5 to 1 compression ratio, I think that should work and not pop to many gaskets Any input on this buildup is appreicated, but the block is the main thing, now I can go find one and start on the lower end of things. Thanks guys

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Arrest ME Red 1994 Camaro Z28 Convertible
just a chip and a muffler, well maybe some headers
http://home.attbi.com/~mycamaro/

 

I would think making a 2 bolt block into a 4 bolt splayed block would be a perfect choice.

Buy the caps and get the machine work done...Viola...Goodlock man



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Denny Villemure
1989 Camaro IROC-Z Convertible, 305 TPI, 2.73 Gear, Flowmaster 2 chamber. 15.60 on motor, 14.20 on a 75 shot from NX. Woo hoo!
www.denny.cz28.com

 

All depends - can you hit the same clamping force that was used when the block was originally line-bored? If so, nothing really changes and you don't need to hone the block.

On the other hand, if the cap clamping force changes due to the change from bolts to studs, then it's not a bad idea to clean things up with a quick hone of the mains.

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1996 Impala SS - LT4 396, T56
1996 GMC K2500
1992 Buick Roadmaster Estate Wagon

 

Uhhh...correct me if Im wrong, but if you're going to go forced induction, and you've already got the means and the intention of building a custom shortblock, isnt 9.5:1 a little high?

 

9.5:1 to high, for a toy? man I would say too low I would say shoot for 10-10.5:1 and race gas only, afterall it is a toy.

Patrick

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Patrick Carter EX '01 HI
94 Quasar Blue Camaro
396 solid roller with AFR heads

www.fastblackformula.com

 

Yes a toy, but a streetable, bearly, toy. Dont want to have to run to the track to fill up. I figure 9.1 is good. Unless someone has some other input on it?

 

COOL, Rich, Now I have an EXOTIC Race set-up! LOL

Really simple actually.
Dave Brown

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If a little's good,
More is better,
And too much is just right!!!