426 Hemi information needed.

[Brutalform]

What year did Mopar start using 16 spark plugs on the 426 Hemi? And was it a race version only?  

[Ace-Garageguy]

Opinions vary.

There are factory pix from 1970 showing a twin-plug head, and the '73 catalog shows them with a Mopar Performance part number.

Intended as a race head, though people have run them on the street. 

[gtx6970]

Mid 1970 season on a limited use. About the same time as pro Stock first came onto the scene , Earilist Ive seen them is the 1970 Sox and Martin Cuda

Became much more common approx 1971 and 1972

 

They were an over the counter race car part only from both mother Mopar and the aftermkt .  never offered for street use, but like as mentioned some ran them on the street.

[TarheelRick]

2 minutes ago, gtx6970 said:

They were an over the counter race car part only from both mother Mopar and the aftermkt .  never offered for street use, but like as mentioned some ran them on the street.

Not trying to be a smart alack, but has there ever been a "factory race-only" part that did not see some street use?

[Deuces]

I think Dick Landy had a hand in the design of those heads.... Look it up!... 

[Brutalform]

Thanks for the replies. The reason I was asking, I just bought the Moebius California Flash, AND the Melrose Missile, and was thinking of adding them to these cars engines. Maybe I’ll build the Flash car as a period correct car, with the 8 plug, and the Melrose as a modified street car, with the 16. I wouldn’t want it on a car that would have never had them on it in the mid 60s. 

Edited January 3, 2019 by Brutalform

[Force]

The twin plug D5 aluminum Hemi heads was developed in 1970 and after them came the D6, also aluminum and twin plug but with a more raised exhaust port.
So no twin plug heads was available for the 1964 A864 or 1965 A990 Race Hemis at that time.

Edited January 4, 2019 by Force

[afx]

https://www.mecum.com/lots/SC0516-243211/1971-plymouth-hemi-cuda-pro-stock/