[Rob94hawk]

My block comes in soon. The specs below are what's on the receipt. I've always wanted to do a big cube LT1. What's reasonable for big cubes on the street? It seems anything with a 4.125" stroke gives me an unfavorable rod/stroke ratio. But I know people here have build some wild street engines.

Possible to squeeze a 6" rod with a 4" stroke or bigger on a standard deck SBC with this deck height?

Things to consider: I will be using E85 & a T56. Max bore can be 4.2" but probably will start out at 4.125" or 4.155"

SPEC EVOLUTION Iron Block:
• Gen2 LT1
• 9.025" Deck
• 4.120" Rough Bore
• 350 Main Journal
• Machined to Accept 1SPEC One Piece Rear Main Seal Adapter
• SBC .904" Lifter Bores
• 55mm Roller/60mm Babbit Cam Tunnel
• .391" Raised Cam Location
• 7/16" Head Studs

 

[18degsbcregal]

I’d do a 406-421, you’ll have a hard time getting an LT1 style head to keep up with much more than that anyway, unless you switch to the Gen 1 stuff. 434 with a 6” rod gets you a 1.000” compression height piston @ 9.0” deck height. It can work, but I’d imagine it’s a trade for long term durability. Just my $.02

 

[434 nova]

421 sb2 heads and a lot of nitrous. My buddy has a 396 lt1 with Pontiac 867 heads converted for reverse cooling.

 

[Rob94hawk]

I’d do a 406-421, you’ll have a hard time getting an LT1 style head to keep up with much more than that anyway, unless you switch to the Gen 1 stuff. 434 with a 6” rod gets you a 1.000” compression height piston @ 9.0” deck height. It can work, but I’d imagine it’s a trade for long term durability. Just my $.02

Well we already know SB 2.2's have worked on this platform and Chad Speier has someone to convert any of his heads onto it as well so we got the cylinder head problem worked out. Just have to figure out what direction I want to go. NA or turbo.

 

[Rob94hawk]

421 sb2 heads and a lot of nitrous. My buddy has a 396 lt1 with Pontiac 867 heads converted for reverse cooling.

Yeah the bore on this block should really open up those SB 2.2. Was looking to grab a pair on ebay for cheap.

 

[18degsbcregal]

If you’re looking to do a power adder, I’d stay with the 3.75, 3.800, or 3.875 stroke. I’d even do a 5.85 rod with the 3.875 stroke. The better ring situation will let you get after it harder, which will make way more power than having 20 more cubes and having to neuter the tuneups to keep it safe. The 5.85 rod can help open up the tuning window a little too, as the dwell time is less

 

[taj362]

If you’re looking to do a power adder, I’d stay with the 3.75, 3.800, or 3.875 stroke. I’d even do a 5.85 rod with the 3.875 stroke. The better ring situation will let you get after it harder, which will make way more power than having 20 more cubes and having to neuter the tuneups to keep it safe. The 5.85 rod can help open up the tuning window a little too, as the dwell time is less

Spot on. Your crankshaft will be a bit stronger too.

 

[n2omike]

Shafiroff use to sell a street 472 SBC. It was built with a raised cam tunnel block and 0.300" raised deck Dart block. The bore was 4.200" and had a 4.25" stroke. Between 630-675hp pump gas with a 6500 RPM redline. A good friend of mine bought one with very little use for $8k... and it RIPS. Doesn't need to rev super high to make power. Was recommended to NOT use nitrous with these engines.

Horsepower/Powernation has a video of the engine details that can be found with Google. This was back around 2006.

You can Google Shafiroff 472 for more info. Was NOT cheap.

 

[1963 corvette]

You want big cubic inch change to different bore space.We have a couple over 500 inch.

 

[18degsbcregal]

^^^ I’ve heard of some of the 4.5 borespace stuff at 4.310” bores?

 

[INTMD8]

That's neat, I didn't know that block existed.

 

[ChopperScott]

^^^ I’ve heard of some of the 4.5 borespace stuff at 4.310” bores?

How about 4.6" bore centers with 4.400"-4.500" bore?

CFE Develops Monster 600-cubic-inch Small-block Engine

The engineering wizards at CFE Racing in Michigan have designed a heart-stopping 600 cubic-inch engine that can support huge horsepower levels.

www.enginelabs.com

 

[1963 corvette]

^^^ I’ve heard of some of the 4.5 borespace stuff at 4.310” bores?

Maybe / could be.

 

[Rob94hawk]

You want big cubic inch change to different bore space.We have a couple over 500 inch.

M&M/1Spec's not casting LT1's in bigger bore space. They wouldn't even do it with a taller deck so we get what we get and happy to have it. Especially since Dart fucked us all over 15 years ago. Glad it didn't happen with Dart. They don't have the ingenuity to create a block like this with all it's features.

 

[Roller2Solid]

I try to avoid anything with an optispark like the plague so I’m not knowledgeable on anything LT1. What are the horn like bosses in the lifter valley for? What are the other features of the block? It looks great. Good luck with the build!

 

[Rob94hawk]

I try to avoid anything with an optispark like the plague so I’m not knowledgeable on anything LT1. What are the horn like bosses in the lifter valley for? What are the other features of the block? It looks great. Good luck with the build!

EFI Connection has a LT1 specific harness to use coil on plug & Holley Terminator/Dominator ECU's as well as LS 411's.

Specifics on this block:

Products – 1SPEC

1spec.net

 

[NitroFun]

Not enough deck height to build big cube in my opinion.

 

[408 Nova]

I would build a 4.125" x 4" engine to start with.

With the raised cam, you won't have to run a reduced base circle cam.

If it were mine though, I'd run 400 mains for a stronger crank.

 

[67shoebox]

Ron Rhodes 550cubic inch SMALL BLOCK 4.6 bore 65k BES dammmmmmmmmmm it

 

[Outlaw Bill]

4.155 bore with 3.900 stroke is all that I would feel confortable wtih in a 9.0 deck height. Possibly less stroke if I had to use a reduced base circle camshaft.