turn a '73 Pig into a '71 Hog? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

thorsgaard · 05-14-2007, 21:36

hey.
My bad.. I used to have a '71 Merc Marq with the 429..was a real good beater, but sold it after highschool cuz I was stupid. Book for it said it had 11.5:1 (or 11.3 to 1- can't remember) compression and hadta have 99.8 octane fuel. I sold the car for 150 bucks

to a guy who wanted it for its "good heads" for a car to build for the local dirt track, which was in its infancy at the time. They won lots of races, and I kicked meself in head e'er time they did..

L8r, bought a '73 Merc with a 429 - 4V in it - thought I'd enjoy some o' the same benefits..but found out it was a pig. (You all are aware of what I wasn't - that the 73 sucked).

Make a long story short - what should I do to make the '73 comparable to the ol' '71? (I believe in laws of physics - I'm sure after reading a little on these pages that nothing too simple can make up for smaller valves and choked ports, along with all the sickening things FoMoCo did to the monster. But I am on a budget - so be gentle)

I'm currently driving an 88 Merc with a sick (comparitively) 5.0L EFI - I know - I know, a lot can be done there, too, but some day, I may wanna put that revamped 429 into the 88. Save the fuelie for a neat Model "T" or sumthin fun like that...

Paul Kane · 05-16-2007, 16:10

The heads on the 1971 model had 77cc combustin chambers, while the heads on the 1973 model had 97cc combustion chambers. Different pistons too, I think.

The 1973 429 could benefit greatly from swapping out its heads for the early-style cylinder heads. There are other subtle changes too, such as cam profile and cam timing (changed at the cam chain).

Paul

thorsgaard · 05-17-2007, 06:03

So what that truck driver Paul ( a guy who used to deliver product to where I work) told me about changing out the timing wasn't a pipe dream after all, then.. I knew the heads was a concern, cause that's what the race guy had wanted in the first place.. Yeah, cool! Thanks Paul!

Well, I'm going to start a build after this summer, so I got lots of time to study!

TFOB · 05-20-2007, 13:24

Quote:

Originally Posted by Paul Kane

The heads on the 1971 model had 77cc combustin chambers, while the heads on the 1973 model had 97cc combustion chambers. Different pistons too, I think.

The 1973 429 could benefit greatly from swapping out its heads for the early-style cylinder heads. There are other subtle changes too, such as cam profile and cam timing (changed at the cam chain).

Paul

Paul,
WOuld you advance the timing or retard, I think I have the option with my timing set of -4, 0 or +4

Paul Kane · 05-22-2007, 00:15

Quote:

Originally Posted by TFOB

Paul,
WOuld you advance the timing or retard, I think I have the option with my timing set of -4, 0 or +4

Where one might set cam timing on a custom build is dependant on so many things. Without knowing particulars, the safest bet is to set cam timing "straight up" (0* advance/0*retard).

Paul