Hey fellas was wondering do any of you run a big cube smallblock?Have a very very good deal on some 400 bowtie blocks I started with the always popular 383 but came across this.I know 400 are known for overheating but aren't production blocks.Thinking about 434 with F1.Wanting to know if there are any problems useing blocks for street/strip setup.Thanks.

 

Check these guys out:

http://shafiroff.com/ultrastreet.asp

 

You do realize the 400 block will not work in as LT1, right?

 

Hey TJWONG thanks for the link alot of good stuff over there.Engineermike thanks for your info as well.But we were planning to go with something else.Not sure still looking around.

 

how do you plan on making a 434? im just wondering, im working on building a 427 sb right now

 

Well in that case. . . are the Bowtie blocks tall deck? If not, a 434 will be sub-optimal. You see, as you increase the stroke, you have to increase the rod length also to get a proper rod/stroke ratio. If you increase both, you quickly run out of room to move the wrist pin up in the piston. A tall deck block not only gives you more cam/rod clearance, but also allows some more meat on the piston to move the wrist pin up. Think about these rod/stroke ratios:

old 400: 5.565/3.75 = 1.48 (terrible, original 400's are known for egging the bores)
350: 5.7/3.48 = 1.64 (better)
350/6": 6.0/3.48 = 1.72 (best)
441: 6.125/4.125 = 1.48 (bad also)

The 441 we just built uses a Dart tall-deck block and a 6.125" rod, but as you can see, the rod/stroke ratio still sucks. I would have preferred a 6.25" rod with a 4.0" stroke for a ratio of 1.56, which still ain't great. . . but the engine made 680 fwhp with 23 deg, standard port heads.

As far as cooling goes, I'm pretty sure the Bowtie blocks are not siamesed cylinders like the old 400's were. This should fix any cooling issues they had.

Mike

 

4.155" bore X 4" stroke. Same as 427, but .030" over.

 

Hey Mike thanks for the info.Not sure about the deck height will have to check.But I do know that they are siamesed.Was going with a 6 in rod.You gave me things to check into.Thanks

 

ohh makes since, i had been told my block was going to be .060 over to make the 427, maybe the guy just didnt know what he was talking about...I ordered a kit from summit to do mine and im going to take it down to the local engine building guru, Carrol Cottel. Engines dont really make since to me, i learned all about suspension and im just starting to learn engines

 

Hey Mike just went and checked the blocks they are the standard deck height.So what you are saying is that I will more than likely come out better with say a 3.875 stroke or use tall deck block?Thanks

 

A 6" rod with a 3.875" stroke is pretty good (420 cid at .030" over). Any more stroke than that, and you need a 6.125" rod, which probably won't work on a standard deck block.

 

Hey Mike thanks for the info.Help me to understand if I go with a tall deck block then I should use a 6.25 rod?Will this be a good for the 434 idea?Still just kicking around some ideas.Thanks

 

You have to put this in perspective as well, here's some SBC's

Most 383's are
5.7/3.75 = 1.52
6.0/3.75 = 1.6

or a 396
5.85/3.875 = 1.50
6.0/3.875 = 1.54

These are some ratio's that I've seen people use before. If you're looking for a 100,000 mile engine then I would try to fix the ratio, but otherwise its all fair game. Good luck with the project.

 

With a 6.25" rod, I'd say you're good to about 4.125" stroke, but I don't know if that'll fit in a tall deck block. With 4.125" X 4.155", you're talkin' 447 cid, or at .060, it would be 454 cid.

 

I have a question?, who say's or how do you calculate these are proven or correct rod ratios. I have been in the hot rod business for many years and the question comes up from time to time.... and quess what? I've never had anyone give me a good answer to their theory. They all revert to "Smokey Said", you know 1902 ideas. Show me the light.