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the cubes will help more if you have the heads to match. if not it probably wont make much difference. as far as the blocks go it depends on what your goal is. factory sb are pretty strong imo. there are lots of good builders on here. Dan is doing the machine work on my stroker now.

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who are some other builders on here that I can get in touch with for this? I know Brian at IMM is one, Competition Wedge another, but who else is there?

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I like the 4" 6.123 rod combo but I don't think I'd hesitate to run the 4.125 with the 6.2 rod and the SBC journals with a set of Brian's RHS heads. spread the lobe centers out a bit (at least 110) and try to shift some of the massive torque upstairs which will also help your power curve above the peak, the curve will be more linear (less abrupt peaky) as well which should be easier on the block overall with the heads you are planning. I would lean toward a 340 victor with some plenum work, again you don't want or need a ton of help in the upper bottom range once you give it some throttle, a good single plane will actually help make the combo more tractible/predictable off idle and in rainy conditions, especially in a nose heavy 4 speed car. A Hydraulic in the 242I/248E range or a solid in the 250I/256E range should be about right for the best balance for broad flat torque and strong top end power with an 850'ish double pumper. ~18-22 initial with another ~12-14 in the distributor with a relatively slow centrifugal advance will make it a very good steet performer without it blowing off the tires around every corner like a too quick advance will do....unless you're running fat and very sticky meats.

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Well Said!

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you would be way ahead of the game to get with a builder and have them spec out your motor. save you a lot of trouble in the long run

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i agree with Tony, im starting to gather parts for my budget R5 421" and helps to get good advice from guys that has been there and done it.

Bob

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(I've bought parts and services from 2 in this very thread ), a lot of these guys I've known for years...even the ones I 'debate' with from time to time, I think we still respect eachother's opinions and we're all still 'buds'.

A lot of these guys volunteer VAST amounts of knowledge and experience and deliver the hard core content to this site, give 'em a shot

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hey, i resemble that remark.
sometimes a lively debate nets some great information to share and that's usually a good thing.

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Matt,
There are a few reasons to not bother going beyond 4". The return on investment for the expense of custom parts and shortening service life just don't make sense to me. I decided to ask a few questions of guys I consider knowledgable and the biggest seems to be the pistons with indeterminate service life as a close second. Noise will also be a factor using a piston that short in a street car. That can be addressed with offsetting the pin but you'll need to work with the piston manufacturer to get something that addresses the issues as best as could be.
IMO - Build a 4" arm, forged crank setup, with reasonable heads, and worry about "bigger" and "more" when you've already maxxed what the 4" engine can do for you. If bigger wasn't better we'd all have 318s with 360 pie tins. But there comes a time when return on investment ends up making bigger less better.

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