77/78 ford ltd/ mercury marquis 460

[ALMACK]

Originally Posted by Billy Nees

Ya know, I really have to ask, how is this combo bogus? It's got an intake port that wants me to try and find someone that can make it smaller and an exhaust port that's not all that good. It's got a big camshaft and big valves but such low compression that you can't really put a "big" cam in it. All but the 74 can only use the small Motorcraft 4350 carb(700 cfm?). It's got a short stroke(relative to the size) and the rotating mass is probably the heaviest of any big block. I can think of a couple of 455 Buicks and Pontiacs that look better on paper. Not to mention that they come in cars that look like the box that my Grand Prix came in and IT'S a box! It must be because they're such a well kept secret that FFFord guys don't even know about them(or choose to not know).

^^ agree

From previous experience with my mid 70's 460s, these are my observations:

The exhaust ports in stock form on those D3 heads are horrible. If you are lucky and find some D3 heads without the A.I.R. injection holes, then grab them. Those bumps in the runner really hurt exhaust flow.

The intake ports in my opinion are way too big. Port velocity is lowered because they are so big.

That 320 factored hp seems a bit high to me. ( considering the valve lift specs and poor exhaust)

Good luck on the LTD build.