stage 1 blocks

[GBGN1]

Ive seen a few of these around lately.I know the 3.8 block has a problem with cracking.Could someone explain the benefit and problem with going with one of these blocks over a girtled 109 or a stage 2 block for a 600+ hp street/strip motor.
Thanks

 

[blackgn1]

They want to crack in the freeze plug area. 600-700hp area a 109 block should be fine. Stage blocks are expensive to build. You will want to use forged crank. Good pistons and rods. With a high dollar block you will want to use really good internals. You wouldn't put stock internals in a stage block. Just an expensive build not that a good 109 isn't.

 

[turbofabricator]

StageI blocks are essentially rejected StageII off center blocks. (same casting number) They may have too much core shift, angled head bolt holes, thin deck, thin here or there, ect., ect., ect. Nothing wrong with a 109 block at 650 Hp, well preppped, that is. Girdle or steel caps and well machined with no detonation a 109 block will live long. Detonate a StageI or II block at 650 HP and you can kill it, too. Tune is more about longevity than the basic block. Either choice is going to be expensive to build. If the extra $1k won't kill you, go StageII.

 

[750H.P.V6]

Ken is right about Stage I blocks being Stage II blocks that weren't up to spec. 3.8 Stage I's and II's have the same problem as they like to crack between the freeze plug holes on the side of the block. Once they crack there isn't much you can do with them.

For a 600 - 700 H.P. street / strip engine I think a stock block with a girdle and some forged internals including a decent crank and rods will work fine for you. If you plan on stepping it up later drop the coin and buy a 4.1 liter off center or an on center block Stage II block.

Neal

 

[d90dan]

Hi Neal!

After a few hundred runs the main webbing cracked on one of my 109 builds. All forged/billet internals and 3 caps, don't think I had a girdle on this one. Probably over 700hp, ran 9.8's @ 137, 3500lbs.

I think the 109 will last for awhile at higher HP, but stage II or aluminum is the best way to go if it's in the budget.

 

[750H.P.V6]

Hi Dan!

Good to hear from you. Glad to see the car is running well. I think you're probably right about the stock block being able to stand up to a bit higher H.P. level than I stated.

I think for 90% of guy's a stock block will do what they want and beyond that it's a slippery slope and things go from being expensive to even more so.

Tell your Dad I said Hi.

Neal

 

[GBGN1]

Thanks guys for your opinions