Mopar Action On-line – Tech Questions


Tech Question

Wesley Johnson, Winnipeg, MB, Canada, 1967 Dodge Coronet, 500 stroker

I’m starting to plan a stroker engine build up for my ’67 Coronet. I’mthinking of going one of two ways: #1: a 400 block w/a 4.15 crank and 6.786rods, or, #2: a 440 block with the same crank/rod combo. What’s the betterchoice? I’m partial to the 400 stroker due to the stouter block (shorterdeck and beefier main web area) and smaller/lighter package, but amconcerned over the short pistons with the small contact area that theirskirts have and the higher side loading and just how streetable are theywith the oil ring support due to the pin boss in the oil ring groove.
I’ve also noticed that on certain big block Mopar-dedicated web sites 4340stroker cranks and 4340 rods are dirt cheap. To your knowledge are thesequality parts or should they be steered clear of?


I guess I’d have to say: “It depends”. Like many things in life, enginedeisgns are, to a certain extent, all compromises. It depends…on how muchyou want to tilt the paramaters towrads light weight, compactness, HP, etc.,and away from longevity, low oil consumption, and durability.

As far as main web area, there’s no difference that I’m aware of.

Oil rings in the pin boss area are definitely not a great durability idea.

Long skirts, rods, etc., are all durability and longevity pluses.

You didn’t mention the intended application for the engine, but you didmention the word “streetable”. Given that, I’d go with the 440 block. Or,build the 400 a bit smaller – 3.75″.

Virtually all those low-end forgings you speak of seem to come from the samefoundry in China. Some are finish-machined here, some over there. The basicforging quality seems to be quite goood, at least in the last 5- 6 years orso (some of the early stuff had virtual lumps of charcoal visible….)



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