Maverick 302 Timing Question

I was curious:

Why are the specs on timing for a 1974 Maverick 302 10 BTC when all other years are 6 BTC?

 

One word: Emissions.

 

Interesting factoid there, Doug.

 

Ford did all kinds of goofy things in the 70s for emission purposes. They played around with the dual vacuum cans on distributors, one can (at the front) advanced ignition timing, the other can (right next to the distributor) retarded ignition timing. They probably had to start with more initial advance to make for the amount of retarded timing dialed into the retard can. As with most of their ideas on emissions it didn't work very well. Everybody I knew used to disconnect the retard can.

The dumba$$e$ raised the block deck heights to put the pistons further in the hole to lower compression then couldn't figure out why the engines pinged. Duh, excessive quench distance between the piston and the head deck. So then they retarded the cam timing and things got even worse yet. When the 5.0 came out they finally realized you can have decent timing (ignition and valve) and higher compression and still get good emissions if you get the quench distance correct. And these guys were high paid engineers that didn't know what the average hot rodders knew.

 

Yeah, I was wondering the same dang thang. And of course the 302 I have happens to be the 74 model year.

I set mine at 8* and it seems to pull fine. Still smokes like crazy though. I think it may be cracked valve guide seals.

Anyhow, I have a 351W that should be taking up residence in my engine bay pretty soon and it runs like a champ. (Shock towers.....)

 

I do believe Craig is right on......Emission standards,maybe smaller valves also

 

Well if we want to find out about the valve size then I can pull the head off the engine and measure it.

We just might be able to see why Ford did what they did to the 74 model 302.

Anyone interested?

 

There are a lot of reasons for the difference in inital timing.
A change in compression. The 73-76 block decks are higher by about .025", the pistons are dished. This changes the combustion propagations.
A difference between manuel and auto trans and with or without A/C as well as changes to meet the changing emmissiomns regulations.
In some cases the cam timing was retardrd.
The best engine was the 71 year for power,

 

If it wasn't so close to the Roundup I'd take my cylinder heads off.....time for a overhaul any way