Iron Or Alloy Heads For Built Hemi

Tech Question


Richard Hudgins, Oneonta, AL, 1970 Dodge Challenger 426/472

Rick, a month or two back I asked you about whether Ishould use aluminum or iron heads for my mild stroker street Hemi, andsiamese or standard block. I have since bought a set of Indy Hemi heads andam looking at a repop used std. type Hemi block (needs 1 sleeve), both at abig discount. Thanks for the advice!

My next question is, if you were me, building a rather mild (but verydurable) 4.15 stroke street Hemi, would you go to the trouble of usinglonger rods (7.1″ or 7.2″)? Or would you just use the stock 6.86″ rods, andlive with the lower rod/stroke ratio? Being a Smokey Yunick disciple, I’vealways leaned toward longer rods, but does it really affect power anddurability in a motor like this? I’ll go with what you say on this, andthanks for the help.


Richard, the biggest advantage to the longer rods is longer piston (skirt)life and reduced cyl wall wear. But, frankly, even with a 6.86″ rod and4.15″ stroke, the ratio is 1.65:1, almost identical to a stock 350 Chevy. Iknow that’s little consolation, but, since I doubt you’ll be putting 100,000miles on this (that’d take about $35,000 worth of gas at today’s prices!), Isay: Don’t worry about it. The money’s probably better spent elsewhere(oiling system, Schubeck lifters, etc.)

Speaking of Ol’ Smokey (RIP), did you read his last book (“Best Damn Garagein Town”)? While it sorely needed an editor (seems to have been printedpretty much as a transcript of him talking into a recorder), and I suredidn’t agree with all his tech “ideas”, it’s a helluva read.


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