Many moons ago I used a set of those on a 396 in my ElCamino, they worked good I could smoke the tires all the way into high gear with no effort!..
I've got a pair on my daycruiser. I know they are closed chamber rectangular port heads. Anyone have experience with these? They work great so far and I like em.
Heres the MORTEC description
3964291....69-70...rect..CLOSED..396, 402, 427, 454, 109cc chamber
Large or small hex spark
plugs used
Many moons ago I used a set of those on a 396 in my ElCamino, they worked good I could smoke the tires all the way into high gear with no effort!..
Well they were standard issue on the 1970 LS-6, so ya, they make decent power. I run them on my 427, if your 291's are unmolested they are worth a few bucks to the original muscle car crowd, these came on L-78, L-71, L-72 and LS-6's in '69 & '70 as you mentioned. My plan is to sell mine and replace them with some form of an open chamber head.
had them on my 69 chevelle ss and loved them. work great and better with 1.88 exh valves.
Great! Thanks guys. I have experience with 990 and 188 heads but wasn't sure about these. They do very well on the motor.