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351W Conversion Questions

75Bronc

Sr. Member
Joined
Feb 5, 2008
Messages
425
I just picked up a 1990 F250 4x4 with a ZF5. I have been reading a lot of threads. I want to use the engine and transmission out of the F250. I currently run FiTech, and will be installing this on the 351W. I have read that the F250 oil pan should work. I will be moving the radiator forward to clear the front engine dress (serpentine) and fan. I have a 2" body lift and I think it should clear the stock hood with low intake manifold (edelbrock performer). I do have some questions:

Is this a decent 351W? I have read they are low compression. Are the heads good? Truck is low miles, no smoke. But doesn't feel like a power house. I'm sure the bronco is lighter and will feel a little more seat of pants power. Definitely should have more low end torque.

Am I going to have clearance problems offroad with the F250 pan?

Is the F250 alternator too much for the stock wiring? What is needed to adapt?

Can I use the F250 power steering pump?

Does my exhaust need to be altered? Should I use the F250 manifolds or the stock bronco manifolds? (Don't want to spend for headers)

Will the 351W distributor work with my stock bronco ignition?

Will I feel an increase or decrease in power over my mild 302? (302 has Comp cams XE256H and matching valve springs, bored slightly)

Anything else I am forgetting? Anything else I can use from this truck? Anything I shouldn't use? Is this a good plan for a guy on a budget? I can work steel pretty well. Moving the radiator forward should not be much of an issue.

Thanks for your input. Your experience is appreciated!
 

rguest3

Contributor
Bronco Guru
Joined
Dec 13, 2012
Messages
3,778
If you use a 3-Core radiator and a 1/2" spacer and rigid 17" fan you do NOT have to move the radiator support forward. The Ford F-Series Serpentine clears easily. I have done this on many 351Ws and two 347s.

You can use the truck 351W Pan.

Edelbrock 351W Performer with FiTech will clear stock hood with 2" Body Lift.

1990 Distributor will not work with Stock Bronco ignition.

Your 302 has a nice torquey Hydraulic Cam. The 351W will have more torque and also has a Hydraulic Flat tappet Cam. I would recommend installing a XE262H Comp Cam in 351W and some Edelbrock 170cc Street heads. It would be a very nice street motor with the FiTech. Gonna need better exhaust though.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
Good engine
There is a little corner of the pan that will need clearancing. Mine self clearanced and was fine
Need to check what was used. Probably a 2G which you don't want. Use your old one before keeping the 2G. If a 3G, you will need to change the charge wire and forget about the amp meter in the dash
The F250 power steering pump can work, probably need adaptor line as it is probably a metric line. I forget the change over
Exhaust will need altering. The F250 manifolds may fit, but the Bronco will will (but the Y-pipe joining them will be off)
The EFI distributor will NOT work with present duraspark. No mechanical advance, the EFI does it all in the computer.
You should feel more grunt, but HP may not change much. That is the torque speaking to you.
 
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75Bronc

75Bronc

Sr. Member
Joined
Feb 5, 2008
Messages
425
Thanks for the reply! Do you have part numbers for the spacer and fan? What size does the F250 have? Will I still use a fan clutch? Thanks!
 
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75Bronc

75Bronc

Sr. Member
Joined
Feb 5, 2008
Messages
425
What distributor will I need? I will want to keep vacuum advance. Will a distributor off a carbureted 351W have the right gear for my cam? Any suggestions on which distributor is best?

Will the stock bronco alternator fit in the F250 bracket? Will it accept the Serp pulley?
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
The '90 should have a flat tappet cam. You can confirm when you pull the intake. Duraspark ignition (factory electronic)? Any 351W from the mid 70's to mid 80's. Aftermarket will probably get you a more adjustable advance curve that is easy to change. No preference except stay away from the cheap GM HEI conversions (they are known to break shafts for no reason.)
 

rguest3

Contributor
Bronco Guru
Joined
Dec 13, 2012
Messages
3,778
The F-250 Fan with the clutch will not fit.

Use a 1/2" spacer and rigid 17" reverse rotation fan. Flex-a-lite and others make one.
 
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75Bronc

75Bronc

Sr. Member
Joined
Feb 5, 2008
Messages
425
Is there a 3G alternator that will fit in the F250 brackets? I know Wildhorses sells one, but I'm looking for a stock replacement I can get at a junkyard or part store. I looked at newer F250 alternators and the mounting holes go side to side, on my f250 they are front to back.

Will my stock alternator fit in the F250 brackets? And will the pulleys interchange?
 

KyleQ

Bronco Guru
Joined
Apr 24, 2008
Messages
5,480
Explorer serpentine is another option - the plastic clutched fan pulls a TON of air and doesn't rob horsepower like the solid fans do.

A 3G out of a Taurus will bolt onto the stock accessory drive - not sure on the F250 stuff.

I'm running a SUM-850072-1 distributor with a MSD 84211 phasable rotor. I'm running a built 351W with Fi-Tech 600PA and a MSD box and it runs awesome with the factory spring advance setup.

Hedman HED88400 headers are $175 and will fit with zero clearance issues with your body lift - they have nice ball flange collectors as well.
 
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75Bronc

75Bronc

Sr. Member
Joined
Feb 5, 2008
Messages
425
I might have to try those Heman headers. I definitely want to use the F250 serpentine system. I want it to be simple, everything from one vehicle (transmission, clutch, engine, front dress). I want to limit the number of donors, I don't want to try and remember all this when I go to the part store. And I have everything already, trying not to spend unnecessary money.

Is the 2G that bad? I am all for updating to the 3G if it will fit in my stock bracketry and work with the F250 front dress. If anyone can confirm what vehicle to pull an alternator from, that would be great!
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,833
The 2G was a manufacturing simplification. All the wires (including the high amp charge wire) are push on spade connectors. the voltage regulator is internal. Same output as the older 1G that worked well for a couple of decades before. The 2G has no performance updates, it was only there to make for quicker work of slapping parts together on the final line. The spade connectors are very well known for getting a little corroded and going into melt down. The 1G is better than the 2G. The 3G is when they started getting serious about making alternators that were actually a better unit in both quality and output. They also learned there lesson and went back to a stud terminal on the output wire.
 
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75Bronc

75Bronc

Sr. Member
Joined
Feb 5, 2008
Messages
425
Thanks for the information of the 2G and 3G.

Can anyone verify which 3G will bolt to my 1990 F250 Bracketry?

Thanks!
 

RPM289

Sr. Member
Joined
Jan 4, 2008
Messages
835
Easiest way to see is take your old alt and hit the salvage yards i think a mustang or tbird 3g will work but compare to be sure.
 
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