258 specs

superhog88

does any body know what the rod journal size and the rod length for a 258, 4.2 and the 4.0 thanks

ironman_gq

they both share the same journal size but one has longer rods than the other and a different stroke, I think its the same bore too

superhog88

looking for dimensions

tufcj

The 258 is a 4.2l.

4.2 L had a 3.895" stroke, the 4.0L had a 3.44" stroke.

LENGTH ENGINE YEAR PART# FORGING# WEIGHT (g)
5.875” 232 1964-66 3172341 154 660
232 1966-70 3180444 707 700
258 1971-81 3180444 707 700
258 1982-88 3237812 unknown unknown
6.125” 199 1964-70 3173210 207 660
232 1971-79 3173210 207 660
4.0L 1987-95 53020126 544 660

I believe the rod/main journals are the same. Specs here:

http://www.matadorcoupe.com/images/crankrodspecchart.jpg

Bob
tufcj

ironman_gq

I take it your building a stroker 4.0. I think JP magazine did one of these a few years ago and after boring they ended up with a 4.6L with close to 300hp

superhog88

thinking about it. 505 performance came out with stroker kit that takes it to 5.0L. was curious how they achieved it? did some number crunching and it looks like the stroke is 4.1in or more. if they are using a 4.2L crank and offset grind it that would put the rod journal at honda journal size of about 1.89 I think. they use ross pistons and it saya eagle rods but they dont give any specs for the rods or crank

ironman_gq

call em up, They probably use custom pieces if they arent factory spec parts.