power from 73 Mach1 3514v

[lewis_dd]

I have a 73 Mach1 with the factory 4v heads with the open chambers and dished pistons. The motor is running really bad but did these engines have any ooomph to begin with? I just got the car like days ago and have not tinkered with it but i think it should break the tires with a 3.25 rear gear. Was the biggest draw back on power the retarded cam timing or the low compression ? How can i get some power so as not to be embarrassses at the stop light without going broke?


help

slow as molassis '73


Darren

 

[jes72mustang]

351Clevelands are capable of everybit as much horsepower as just about anyother engine. It will cost you more to do it than it would in say a 351 Windsor simply because the aftermarket parts are fewer and therefor pricier.

You will hear a lot of different oppinions about v2 vs v4 heads on a cleveland. From my research I have found that the v2 heads are a better street and low end head. THe v4 heads especially the closed chamber version is said to have more horsepower in the upper rpm range.

How many miles are on your car, has the engine ever been rebuilt? There are a lot of factors that could lead to it seeming so sluggish. It could need a tune-up, new plug oil change. You said that you just got it a few days ago, Take some time and money this weekend and do some general maintenance. NEw plugs, air filter, change the oil, check the timing etc.

Also you didn't mention if there were any engine mods, is it still the original point ditributor? I think you will find with a little effort you can bring some new life to that cleveland and you will be happy with it in the long run. There are a lot of people who love to build these engines for drag racing.

For more information check out this forum:
http://www.network54.com/Forum/119419/

These guys are hard core clevelanders. Tons of knowledge to tap into. Not that there isn't here, but these guys are experts.

Good luck

 

[ddonaca351]

Network 54 guys are a GREAT place for info....

(imho) the closed chamber heads are better than the opens. The opens had very little squish, and so no turbulence, so you get hot spots, etc... usually cant run as much timing, or compression cuz of this. (less power)

Above advice is a must. New plugs, wires, cap, rotor, fuel filter, pcv valve, check timing, change oil, tranny fluid, coolant, belts, hoses, etc... Also run a steady diet of fuel injector cleaner for the first 6-8 tanks, (full strength: 1 bottle per tank, no matter how many gallons it says it treats) to clean out YEARS AND YEARS of neglect and carbon build-up.

After all that I would search on here about tuning the carb with a vacuum guage, setting idle, etc...

If you are needing more power (again imho) the single best upgrade you can put on your car is a good 2.5" d.o.m exhaust system (duals). Magnaflow sells a good one for earlier stangs, might fit the 72-3, Im not exactly sure.

After that a simple cam/lifter/spring swap (with proper carb tuning) should be worth 30 hp with no loss of driveability. ( I like the Lunati bracket master 2 hydraulic )
But any good 1500-5500 / 2K-6K cam should work.

If you have the stock aluminum 4bbl intake it is a good one, keep it. (will go with cam above) If you have the iron 4v intake, THROW IT AWAY (save 40lbs) and get a good dual plane alluminum 4v intake (offy or wieand are ok, the edelbrock performer doesnt match the 4v ports, but the Blue Thunder is the best - imho)

If you have an automatic, you can find headers, if you have a stick (like me) you will need to make your own unless you want big HUGE head tubes that will never work with your combo...
If you have to keep the factory exhaust manifolds, read a book on head porting, then take the highspeed grinder (or dremmel) to the inside of em and smoothe all the rough edges and sharp corners and make sure the ports align. Factory castings can be off by as much as 1/8 inch (air hates to flow over a square ledge).

With the tune up, cam, manifold and ported manifolds you should be out less than 1K, possibly as little as $500, and will probably up your power output by a solid 50hp.

Also if you have an auto, save a few bucks for a shift kit, and a MILD stall converter (like 1500 rpm). It doesnt really up your power output any, but it makes it feel and accelerate better, so the seat of the pants factor equals big smiles. Thats probably another $500 for both.

Good luck with whatever you decide, and let us know if we can help. (pm if need be)

Dave-

 

[Gud T.B. Blown]

If you have an automatic, you can find headers, if you have a stick (like me) you will need to make your own unless you want big HUGE head tubes that will never work with your combo...

here is another option for headers if you have stick besides hookers.
http://www.fordpowertrain.com/opening.htm
the guys on network54 say they go on easy and make good power.
fwiw i have a 4 speed with hookers on my '73 albiet with a '70C, and the combo works for me.

 

[lewis_dd]

73 mach update

Thanks Guys;

I found the distributor advance plate stuck and the vacuum advance not working as well. Also the coil had a very bad wire to it (it fell off when i moved it). I am getting some parts together plugs,points (for now), oil,filter, coil, cap,and rotor. Also this car has the edlebrock 4 v intake and the throttle cable is very kinked so i will need to make a bracket to straighten it. It looks like it is binding and i am not getting full pull on the carb linkage as well as no kickdown for the tranny.

i will keep you posted.

i would like to get a set of 4v closed chamber heads and with my dishe pistons should give me about 9-9.5 to 1 compression but for now i gotta run what i brung.

Any sugestion on cam and carb for this . It has an edlebrock 1406 600 cfm vac sec now and i believe all lower end is stock.

thanks

Darren

 

[68RCodeConv]

I have a 73 351-4V convertible....

It has 70K miles on it and the long block (heads, cam, short block) is dead stock. C6 automatic and (originally) 3.25 gears. When I got it, it suffered from a lack of low end power and would not spin its tires. Here's what I have done to it in order to get a little more oomph out of it: changed timing chain to get the cam back to zero, Edelbrock 4V Performer intake, Edelbrock carb, Mallory Unilite distributor with very quick mechanical advance, 3.89 T-lok rear gears, "low gear" kit in the C6 (1st gear is 10% lower), increased the initial advance.

After all these things it still would not spin its tires. So I changed the converter from a 2100 stall (which is factory, believe it or not) to a 2800 stall converter. That single change made more difference in seat-of-the-pants feel than all the others combined.

What I have learned about 4V Clevelands: (1) they like lots of gas on acceleration. Double-pumper or a big accelerator pump shot is a must. I went to a weaker step-up spring in the Edelbrock carb to get it into the power mode quicker. (2) they like LOTS of initial timing. I run about 15-18 degrees. I had to get a hi-torque starter to crank the motor when hot. (3) they just are NOT going to make a lot of power below 2500 rpm no matter what you do. You have to have a lot of rear gear and a loose converter to get them rolling. Or slip the clutch if you have a manual.

One last thing. The factory valves are a 2-piece construction and have a nasty habit of coming apart once they get old and tired. I don't rev mine above 5000 rpm. I have a redone set of CC heads that will be going on soon.

 

[stang302v8]

My only advice is- get a different engine. clevlands ( in my experience) are dogs, no offense. when my factory 302 with the 2 barrel carb was totally stock, stock cam, heads, intake, etc, i was still keeping up side by side with my friends with built 351 clevlands. the 351 c is for long run, and has no power low end what so ever. my buddy has cam, heads, intake, gears, stall convertor, everything u can possibly think of, and it is still a total dog off the line. my 302 had 120,000 miles on it and was running with their 3,000 mile-newly built clevers. i jjust find no hope for those things unless you have A LOT of $$$ and are willing to go all out to make some power. good luck though.

 

[Gud T.B. Blown]

My only advice is- get a different engine. clevlands ( in my experience) are dogs, no offense. when my factory 302 with the 2 barrel carb was totally stock, stock cam, heads, intake, etc, i was still keeping up side by side with my friends with built 351 clevlands. the 351 c is for long run, and has no power low end what so ever. my buddy has cam, heads, intake, gears, stall convertor, everything u can possibly think of, and it is still a total dog off the line. my 302 had 120,000 miles on it and was running with their 3,000 mile-newly built clevers. i jjust find no hope for those things unless you have A LOT of $$$ and are willing to go all out to make some power. good luck though.

that must be why they still use cleveland based heads in nascar.

another thing about clevelands is that you have to get ALL of the parts right when you put them together. without the right cam you going to lose power, especially on the bottom.

 

[lewis_dd]

Thanks Thats why i will only run a cleveland. I ran my convertible at a track with 2.73 gears and my 351 and pulled 14.7 against my buddies same car with a mildy built 302 and he ran a 17. I ran a cleveland in highschool and would pull till the 120 speedo in my '72 grande 2v would bounce off the needle ( 2100 carb had home made drilled out jets when i was 17). never blew one up but never tried to get 600 hp or turn 8000 yet.


I think pop-up pistons , keep the factory heads for correctness, good torque cam like the XE268, good dual exhaust, tune carb (don't know what one to use yet), pertronix conv., new un retarded timing set.

Any other options, opinions, especially on carb.


thanks,

darren

 

[lewis_dd]

signiture

by the way my signiture is from my convertible not the mach i i have now..
i need to change that.

darren

 

[thumper460]

IF your going to rebuild.. then up grade the dish pistons.. but after you get all the "bugs" worked out.. yes the fastest way to power is to find a set of Closed chamber heads, get the compression up !! also if the timing chain needs replaced.. get a good one a advance the cam 4* that will also help the low compression engine!! and RIGHT ON with those heads!!!! they ( those "they " guys) pulled over 550 HP from a 302 in the late 70"s using the 4V heads!! all the power you will EVER need is those Heads!! the 385 series engines ( 429-460s) use the canted valve design.. also the BBC ( yeah.. they were first!!)use a canted valve design, 'cept their runners are messed up.. LOL.
Have fun and enjoy...
Just me..............................

Thumper