351 C modification questions

[spyder210]

Hi all, I may be purchasing a bone stock 71' Mach 1 with a 351 c H code motor that is rated stock with 240 hp and 350 trq. I did some research and i found out that it is a stock 2bbl carb and a 2V cylinder head. Is that correct??? Now, if i took off the stock heads, intake, carb, headers/exhaust, cam, and valves etc...couldn't i install a set of higher flowing 4V heads along with obviously a stronger camshaft, valves, and better breathing intake and exhaust??? I figure since they made 351 c's with 4V heads such as the Boss and Cobra Jet, i could make the swap to a 4V to a 2V as long as i increased intake and exhaust flow and proper camshaft settings. Am i right in this ??? Please correct me if i'm wrong!!! I am coming from a 97 GT vert to a jeep wrangler and now my dad and i are gonna build up this car....please help me get my head straight with this idea!!!

thank you all very much!!!

-Paul

[hobgoblin351]

Spyder, You're definately on the right track. Your best bet would be to find an old pair of Boss351 heads. Big ports, closed combustion chambers, and ready for screw in studs for the adjustable rockers. But think about this: you only really need 4V heads if you are going to be making horse power in the high RPM ranges. There is no middle of the road with Clevelands!

[mustangII460]

4V Is stamped on the corner of the head, if its a 4V head, or 2V. I think it's on the front of the head either top or bottom (can't member) near the valve cover. But it's visable.


Personally I'd keep and use the 2V heads. If your not going to build a monster drag motor. The 2V heads will probably work better for you on the street. The big 2.19 intake valves on the 4V will only help way up in the RPM range.

I would however consider going to a 429/460. The cost to build C motors is about equal to building a 385 series motor.

I never liked the C motor heads 2 or 4V. The exhaust port has a massive dogleg, restricting flow.

good luck

[Rev]

I would just keep the 2V heads with maybe a pocket port and 3 angle valve job. MustangII460 is right here, don't go for the 4V heads for street performance.. Put a street cam (270 advertised duration hydraulic)and an Edelbrock Perfprmer (or Performer RPM ) with decent 1 5/8" headers and 2 1/2" pipes with Flowmasters and you will have decent street performance. You will want 9.5-10 CR for pump gas.

Rev

[joinrdie]

I considered getting a pair of 4V heads when I built up my motor, but decided to stay with the 2V's. Couldn't be happier. I went with a pretty decent street/strip cam (.536/.536), 9.5 compression, a holley 750, performer intake and big-tube headers. I couldn't be happier with this combo for the street.

I guess it all depends on what you want to do with it. I take a certain amount of pride in my Cleveland, just because not a lot of other people have them. Sure you could go faster with a big block for a similar price, but then you don't get the Cleveland stigma, or the Cleveland sound.

You might look into getting Aussie heads. They are basically the same as the 2V heads, but with closed combustion chambers. Supposedly, they give you some serious bottom-end.

[hobgoblin351]

Hey Joinordie, what gears are you running? I'm also running an FMX but with 3.89's outback I'm screaming on the highway. I'm thinking of lowering the gear, or going with an overdrive unit. Either an AOD trans, beefed up of course or an add on overdrive that'll give me a high/low split resulting in 6 gears. What do ya think?