302 vs. 5.0 flywheels - Pirate4x4.Com : 4x4 and Off-Road Forum

littlemule · 03-12-2003, 11:34 AM

I cant seem to get any answers from anywhere else about engine swaps. I have a 302 in my 74 bronco with the original 3 speed manual. I now have an 86 f150 donar vehichle with a 5.0 fuel injected motor that has a c4 auto. I want to know what to do about a flywheel and harmonic balancer, can i take both off of my 74 302 and install them on the newer motor with out any problems or will i have to find an 86 manual motor to take them off of. the other question I have is can i make a 4 speed overdrive manual out of an 84 f150 into a 4x4 tranny by making an adapter to my dana 20 or is that only a 2 wheel drive tranny? thanks in advance

Rogue Bronco · 03-12-2003, 02:51 PM

try searching under 5.0L + imbalance
you'll soon find out why that wont work

emsoffroad · 03-12-2003, 05:32 PM

Balance changed in the 302 from 28 to 50 oz. This was the same time they went to the one piece rear main 8? something. Some one here can give you exact year.

You could make your 2wd tranny into a 4wd tranny if you wanted. But this may or may not be worth your time. You would have to make the adapter to hold the two together, then have the output shaft cut and resplined to fit your case. Your best bet would be to start with a 4wd tranny, bolt the front half of a 203 on it then make the adapter to bolt the 203 to the D20.

littlemule · 03-12-2003, 05:38 PM

do you recomend any cheap easy to find 4wd tranny . and are you refering to making a doubler case from the 203 or just using part of the case for the bolt up? I have 2 dana 20s and always wanted to make my own cold duck case frome one but if the 203 is easier I might just try that. Just give me a little more info

Rogue Bronco · 03-12-2003, 05:48 PM

1980 & older are known as 302's (28oz. imb & 2 piece rear main)
1981 & newer are known as 5.0L's (50oz. imb & 1 piece rear main seal)
you can use your '75 flywheel on the '86 engine, but you'll need to get it re-balanced to 50oz. imbalance (not very expensive).
So use the complete '86 engine (harminic & shit), with the re-balanced flywheel. Bolt up a standard tranny to it and run it.

Rogue Bronco · 03-12-2003, 05:58 PM

As for the T-case dillema
Most 2wd trannies (Ford) are 28 spline.
Most 4wd trannies (Ford) are 31 spline.
I'ld say first decide if ya want standard or auto, then decidde if ya want 1 or 2 T-cases.
Then which two T-cases.
Im 'ass'uming this is going into the EB, so its gotta stay pretty short.
IMO - the best short combo would be a 2wd NP435(4-speed stick w granny low), coupled to a Dana 20. Cheap simple adapter and you've got most of the parts already.
Just need a Ford 2wd NP435.

03-12-2003, 11:34 AM	#1 (permalink)
littlemule Registered User Join Date: Mar 2003 Member # 17743 Location: columbus ohio on the weekends Toledo all week Posts: 216	302 vs. 5.0 flywheels I cant seem to get any answers from anywhere else about engine swaps. I have a 302 in my 74 bronco with the original 3 speed manual. I now have an 86 f150 donar vehichle with a 5.0 fuel injected motor that has a c4 auto. I want to know what to do about a flywheel and harmonic balancer, can i take both off of my 74 302 and install them on the newer motor with out any problems or will i have to find an 86 manual motor to take them off of. the other question I have is can i make a 4 speed overdrive manual out of an 84 f150 into a 4x4 tranny by making an adapter to my dana 20 or is that only a 2 wheel drive tranny? thanks in advance

03-12-2003, 02:51 PM	#2 (permalink)
Rogue Bronco Registered User Join Date: Mar 2002 Member # 10622 Location: Vancouver Posts: 400	try searching under 5.0L + imbalance you'll soon find out why that wont work __________________ '85 Bronco III

03-12-2003, 05:32 PM	#3 (permalink)
emsoffroad Rock God Join Date: Sep 2000 Member # 1802 Location: Shamokin, PA Posts: 1,700	Balance changed in the 302 from 28 to 50 oz. This was the same time they went to the one piece rear main 8? something. Some one here can give you exact year. You could make your 2wd tranny into a 4wd tranny if you wanted. But this may or may not be worth your time. You would have to make the adapter to hold the two together, then have the output shaft cut and resplined to fit your case. Your best bet would be to start with a 4wd tranny, bolt the front half of a 203 on it then make the adapter to bolt the 203 to the D20. __________________ EMS Offroad

03-12-2003, 05:38 PM	#4 (permalink)
littlemule Registered User Join Date: Mar 2003 Member # 17743 Location: columbus ohio on the weekends Toledo all week Posts: 216	double case? do you recomend any cheap easy to find 4wd tranny . and are you refering to making a doubler case from the 203 or just using part of the case for the bolt up? I have 2 dana 20s and always wanted to make my own cold duck case frome one but if the 203 is easier I might just try that. Just give me a little more info

03-12-2003, 05:48 PM	#5 (permalink)
Rogue Bronco Registered User Join Date: Mar 2002 Member # 10622 Location: Vancouver Posts: 400	1980 & older are known as 302's (28oz. imb & 2 piece rear main) 1981 & newer are known as 5.0L's (50oz. imb & 1 piece rear main seal) you can use your '75 flywheel on the '86 engine, but you'll need to get it re-balanced to 50oz. imbalance (not very expensive). So use the complete '86 engine (harminic & shit), with the re-balanced flywheel. Bolt up a standard tranny to it and run it. __________________ '85 Bronco III

03-12-2003, 05:58 PM	#6 (permalink)
Rogue Bronco Registered User Join Date: Mar 2002 Member # 10622 Location: Vancouver Posts: 400	As for the T-case dillema Most 2wd trannies (Ford) are 28 spline. Most 4wd trannies (Ford) are 31 spline. I'ld say first decide if ya want standard or auto, then decidde if ya want 1 or 2 T-cases. Then which two T-cases. Im 'ass'uming this is going into the EB, so its gotta stay pretty short. IMO - the best short combo would be a 2wd NP435(4-speed stick w granny low), coupled to a Dana 20. Cheap simple adapter and you've got most of the parts already. Just need a Ford 2wd NP435. __________________ '85 Bronco III

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