SBF HEADS

Has anyone ran any of the ford M-6049-X307 small block head thinking about up grading the heads on my 69 f100 from the 71 model factory 351w heads. It getting time to freshen the engine plus it is getting hard around here to find the lead additive for the gas to run the old heads. Time I spend the money on having new valve guides and valve job done on them I can put that into new heads. Just wondering if anyone has ran the x307 heads and how they work I not looking make to a 500hp engine just around 300 to 325hp.

69F100 wrote:Has anyone ran any of the ford M-6049-X307 small block head thinking about up grading the heads on my 69 f100 from the 71 model factory 351w heads. It getting time to freshen the engine plus it is getting hard around here to find the lead additive for the gas to run the old heads. Time I spend the money on having new valve guides and valve job done on them I can put that into new heads. Just wondering if anyone has ran the x307 heads and how they work I not looking make to a 500hp engine just around 300 to 325hp.

Those heads are great heads for what they are.

Smallish chambers is not any problem with a 5.0 engine ... getting larger combustion chambers seems to be your only issue.

I seen that they have a x306 also only difference I seen on the description was they had 64cc camber. I think I will go with the 306 head instead of the 307. Randy when I get ready to freshen up the engine I will be getting a hold of you for a new cam for it.

For 100.00 more you can get into the Trick flow 170cc fast as cast head. Viton seals instead of umbrella, bigger valves, a little more compression, 58cc vs 60cc. A lot more head for 50.00 a head.






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Mine are the older M-6049-X302 versions. The higher number is simply a revised head. Mine do not have umbrella seals either.

I had Blake custom grind me a nice hydraulic roller cam to go with those heads and a 351W shortblock. should be a good running machine. Will be some time before get back to working on that combo though...

69F100 wrote: I seen that they have a x306 also only difference I seen on the description was they had 64cc camber. I think I will go with the 306 head instead of the 307. Randy when I get ready to freshen up the engine I will be getting a hold of you for a new cam for it.

The 306 differs from the earlier 303's on two fronts. They have beehive springs and they have a straight, un-scalloped, lower edge so they can be used without any water leaks on sportsman, Boss and other aftermarket blocks which have water cooling holes on the deck down there as long as a matching head gasket to the block is used.
The 307's have the same beehive springs and straight lower edge at the deck as the 306's.

They all use the production bolt down type rocker arms; rollers or stamped.

Thanks Randy. Do you know if the beehive setup from the 307s will plug and play on my 302s???

jbozzelle wrote:Thanks Randy. Do you know if the beehive setup from the 307s will plug and play on my 302s???

As like the 302 production heads, it will depend a lot upon the base circle of the cam.
Those springs will accept over .600" lift.

I was asking more about the valve guide OD and spring seat area of both heads. I should’ve been more clear. Did Ford change that area at all between the different revision numbers?

I have 307's on my 408W right now. X cam , 9.7 compression , air gap intake. Made 480 hp 520+tq . Runs on 87 all day long. I could have "worked" the heads or bought others to make more power. I got what I wanted.

gt350hr wrote:   I have 307's on my 408W right now. X cam , 9.7 compression , air gap intake. Made 480 hp 520+tq . Runs on 87 all day long. I could have "worked" the heads or bought others to make more power. I got what I wanted.

What spring package are you using on them? As delivered from FRPP?

No they floated at 5,800. Took me 4 dyno pulls to single out the cause.I used a spring from Competition Products in Wi. 1.540 single , 145 seat pressure 365 over the nose. I also added a ti retainer and is now good to 6,500 ( I stopped there as power was falling off a bit) 480 peak at 6,100. Ford springs were 95 on the seat and 285 over the nose. More cam would have made more power for sure.  I used the X can for zero maintenance with a "Cobra" rocker.

jbozzelle wrote:I was asking more about the valve guide OD and spring seat area of both heads. I should’ve been more clear. Did Ford change that area at all between the different revision numbers?

On those type single spring heads, NO.
The guide O.D. is a pressed steel guide which is much smaller than the spring seat I.D.
They still used the same thin metal seat I.D. locator insert pressed onto the aluminum casting for a spring seat which is for a single type spring.

gt350hr wrote:No they floated at 5,800. Took me 4 dyno pulls to single out the cause.I used a spring from Competition Products in Wi. 1.540 single , 145 seat pressure 365 over the nose. I also added a ti retainer and is now good to 6,500 ( I stopped there as power was falling off a bit) 480 peak at 6,100. Ford springs were 95 on the seat and 285 over the nose. More cam would have made more power for sure.  I used the X can for zero maintenance with a "Cobra" rocker.

Sorry for the late reply. Didn't see the post update.

Your X307s had the beehive springs originally? The springs from CP are beehive as well? Do you have the part numbers by chance? Did you have to machine the spring seat or valve guide at all?

I'm looking for a good spring that I can just drop in without machining. Not sure such a spring exists... I have a custom ground hyd roller and need a good spring.