302 with 351 firing order???? why?

[BayStYAt]

It would be nice to know what the usage/expectations/goals are.

The “thumper” series of cams is sort of designed to stick a big sounding cam in a stockish motor IIRC.

thats my goal.

[71cc]

With iron heads you really need at least 9:1 compression. Use premium fuel. Compression helps everywhere to make engine more efficient. I'm not a sbf guy so don't have cam advice. Once you've built an engine your driveability experience is mostly influenced by carb, ignition tuning. Then gearing, converter comes into play. Build a durable long block then concentrate on intake carb and ignition. Those three will be worthy of their own thread.

[DuckRyder]

For the sake of discussion I believe this is the cam that is being considered.

http://www.compcams.com/Company/CC/cam- ... =1472&sb=2

FWIW, there are 3 cams in this line. Thumpr™, Mutha' Thumpr™, and Big Mutha' Thumpr™ the Thumpr being the most conservative.

Thumpr™ : High performance street, stock converter ok, best with 2000+ converter and gears. Choppy/thumping idle.

I feel like I should just change the title of this to “Buiding a Marine 302 for my Truck” or something.

[The Bandit]

Something to keep in mind also is that you have a late 60's early 70's 302 block that is meant for a flat tappet cam so kind of stay with a flat tappet cam for that block. If you do go with a roller cam be sure to do your homework as your block, like mine, doesn't have the provisions for a spider tray to bolt to the lifter valley to hold the tie bars in place for the lifters so you will have to get lifters that have the tie bar made to them or have a machine shop drill and tap them in the lifter valley of your block. Also if you decide to go with one of the Ford motorsports Letter cams or something similar you will need a special set of roller lifters to go in your block as a regular set of like HO roller lifters will not work as the cam lifts them to high so that the oil groove around the lifters are out of the oil passage and will starve the back half of the lifters for oil and thats never good...

[BobbyFord]

...Thank you Duck, the Mercury tag only has a serial number.

Merc site has an engine serial number decoder.

[BayStYAt]

...Thank you Duck, the Mercury tag only has a serial number.

Merc site has an engine serial number decoder.

Bobby, I ran the number on their site. No luck.

[BayStYAt]

Something to keep in mind also is that you have a late 60's early 70's 302 block that is meant for a flat tappet cam so kind of stay with a flat tappet cam for that block. If you do go with a roller cam be sure to do your homework as your block, like mine, doesn't have the provisions for a spider tray to bolt to the lifter valley to hold the tie bars in place for the lifters so you will have to get lifters that have the tie bar made to them or have a machine shop drill and tap them in the lifter valley of your block. Also if you decide to go with one of the Ford motorsports Letter cams or something similar you will need a special set of roller lifters to go in your block as a regular set of like HO roller lifters will not work as the cam lifts them to high so that the oil groove around the lifters are out of the oil passage and will starve the back half of the lifters for oil and thats never good...

Thanks Bandit. I’m gonna go flat tappet

[BayStYAt]

For the sake of discussion I believe this is the cam that is being considered.

http://www.compcams.com/Company/CC/cam- ... =1472&sb=2

FWIW, there are 3 cams in this line. Thumpr™, Mutha' Thumpr™, and Big Mutha' Thumpr™ the Thumpr being the most conservative.

Thumpr™ : High performance street, stock converter ok, best with 2000+ converter and gears. Choppy/thumping idle.

I feel like I should just change the title of this to “Buiding a Marine 302 for my Truck” or something.

I would like the Thumper can. Getting a 2000 stall. Probably a better thread title

[BayStYAt]

With iron heads you really need at least 9:1 compression. Use premium fuel. Compression helps everywhere to make engine more efficient. I'm not a sbf guy so don't have cam advice. Once you've built an engine your driveability experience is mostly influenced by carb, ignition tuning. Then gearing, converter comes into play. Build a durable long block then concentrate on intake carb and ignition. Those three will be worthy of their own thread.

71, I think I’m gonna just build the motor with 9:1

[BayStYAt]

...Thank you Duck, the Mercury tag only has a serial number.

Merc site has an engine serial number decoder.

ok I found this.

MerCruiser 225 (4 Barrel.) Ford 302 V-8 1973-1974

My serial number falls in in this range

[Ranchero50]

I think I'd leave it well enough alone as long as it doesn't have excessive wear. 225 is not a bad number to deal with.

[DuckRyder]

I agree based on what we now so far.

I’d fix the leaks and put it back together if nothing looks amiss. From what I can find it seems like it is supposed to have ~9.0:1 compression (which is hard to understand if your head cc numbers are correct) so throw the Thumpr in there if that’s what you want. I bet it would run just as good with the Stock MerCruiser cam (if thats what is still in it) though, it just won’t sound the business...

[The Bandit]

I agree with the above. Clean it all up really well if it shows little wear new gaskets everywhere since it's out and paint it up throw in the cam you want and roll with it.

[Ranchero50]

I'll add that I'd pull the existing cam and figure out what it is before changing. It should be some flavor of OEM cam.

Up at Carlisle a decade ago I dyno'd my '93 5.0 and the car before me, a '66 fastback mustang with a radical cam and dressed to kill looks barely managed 145 hp on the rollers. While running mine the operator commented that a lot of built old school cars just do not perform well and since they sound radical the owners think they are. Mine put down 390 RWHP at 5k which impressed the operator. Told me to leave it well enough alone and I got 100k miles out of it like that.

[BayStYAt]

Ok, I pulled the pistons and the cylinder walls look perfect. The Rod bearings are pretty worn. 75% copper is showing. I found a nick on one of the journals.

Rods are C8OE-A

I am pulling the cam tomorrow and crank tomorrow.

So I am gonna have the crank fixed and go with new pistons, rings, bearings, rods, cam and lifters.

should I go with 9:1 or 10:1 set up?