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300 I6 to V8

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Ribmtrider

300 I6 to V8

Good morning from the upper peninsula of michigan! Thanks for having me here. I am looking for info on swapping the 6 to a v8 in my 1984 f150 flare side. Plan is to do that and lower it. I searched the forum, but the documentation tab show under construction. Thanks again and any info is greatly appreciated.Tim

1984 F150 Flareside
I6 with 3+od manual transmission

Gary Lewis

Re: 300 I6 to V8

Administrator

Hello, Tim! Glad you joined.

However, you may have missed the email you were sent asking you to read the guidelines and then post an introduction in the New Members Start Here folder. We ask that because we hold everyone to the guidelines and since they are posted in the NMSH folder that gives you a good opportunity to see them.

So after you assure us you've read them, and hopefully post an intro, we can discuss the swap. But you are right that we don't have much on it. However we'll need to talk about engine perches and radiators, at the very least.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

IowaTom

Re: 300 I6 to V8

In reply to this post by Ribmtrider

Welcome to the forum, Tim!

I bought my '85 F150 'long bed' from a neighbor because I needed a pickup and had owned Rangers before.
It was cheap but needed virtually everything, with just over 130K miles. The guys on this forum walked me through everything and now I have a truck I take everywhere and haul anything along with the satisfaction of having done it all myself.

If we were closer, I'd buy your old engine & tranny for spares! :-) Good luck with the swap to a V8 and keep us updated as you go.

'85 F150 XLT 4X4 with 300 c.i. six & NP435 four speed.
'63 Studebaker Avanti - 350/TH350
'59 Rambler Super - OHV 6 with 3-speed OD
'58 Studebaker Scotsman sedan - 289 with 3-speed OD

Ribmtrider

Re: 300 I6 to V8

Thanks Iowa Tom, where in Iowa? I travel a lot, and spend mucho time on I80 in Iowa! I’m hoping I can still use the current transmission, but could potentially deliver the engine. Anyway I do like this I6, but I have an autistic nephew that is REALLY into loud fast cool vehicles, so I’m kind of doing this for him, but for me too! I’m in Ironwood MI, where we just got 13” of snow

1984 F150 Flareside
I6 with 3+od manual transmission

Gary Lewis

Re: 300 I6 to V8

Administrator

Tim - Would you like to be on our map? (Bullnose Forum/Member's Map)

As for the swap, the "small block" bolt pattern transmissions fit the 300 six & the 302 and 351 Windsors. So you can keep the same tranny, but will probably need a larger clutch.

And the radiator for the 300 has its openings on the opposite side from the V8's, so you need a different radiator.

Then there are the engine perches, and you can see what I'm talking about on the page at Documentation/Exterior/Frames/Engine Perches.

Plus there's a bit of wiring to be changed as things are in slightly different positions with the 6 vs the 8's. For instance the coil wires, the oil pressure sender, and the temp sender are all in different locations so you may have to lengthen/shorten the wires.

Obviously the exhaust is different. And the fuel line.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: 300 I6 to V8

Administrator

In reply to this post by Ribmtrider

Pre '85 (before EFI) 302's & 351's (H.O. up to '87) should offer the proper wiring for oil, temp, distributor and coil to use the DSII ignition module at the driver's plastic inner fender well.
So if you're working from a donor pickup the V-8 engine harness should plug right in place.

The Windsor engine perches will bolt to the back of the crossmember.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: 300 I6 to V8

Administrator

Good point, Jim. I was thinking about modifying what he has, which should be DS-II. But if he can find a donor then so much the better.

Gary, AKA "Gary fellow": Profile

Ribmtrider

Re: 300 I6 to V8

From what I read the I6 and small block bell housing are the same so it should bolt up ok?

I may have a lead in a nice 460, doable or am I creating a lot more work than using a sbf?

1984 F150 Flareside
I6 with 3+od manual transmission

ArdWrknTrk

Re: 300 I6 to V8

Administrator

You're going to need a new gearbox and engine perches that are unique to the 460.
Enough suspension to handle the weight and torque, which is likely to lead to eight lug axles.

Definitely a much bigger exhaust and probably a bigger radiator and fan shroud than you'd use with a Windsor.

Hey, I'm a 460 fan and it's up to you but (as Gary can attest) the rabbit hole gets pretty deep.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: 300 I6 to V8

Administrator

Don't forget that the 460's engine crossmember is dented for the oil cleaner. And if you don't have that then some people use different perches that raise the engine up or a remote oil cleaner.

I'd go with a 351W.

Gary, AKA "Gary fellow": Profile

Ribmtrider

Re: 300 I6 to V8

In reply to this post by Ribmtrider

Thanks, you talked me out of the 460!

1984 F150 Flareside
I6 with 3+od manual transmission

Ribmtrider

Re: 300 I6 to V8

In reply to this post by Ribmtrider

Ok, so if I don’t end up with a donor, where would be a good place to get perches? Thx

1984 F150 Flareside
I6 with 3+od manual transmission

Gary Lewis

Re: 300 I6 to V8

Administrator

I think you might be looking for a salvage. But, you might find someone on here that has them. You could post in a new thread with the title of what you are looking for.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: 300 I6 to V8

Administrator

In reply to this post by ArdWrknTrk

Jim, one of the big issues with these trucks with a 460, there are 3 radiators, 6 cyl. V8 and Diesel. All the v8s got the same radiator, whether a 302 or a 460. The only change is the mount revision in 1984.

I have already decided the next time I have to put a radiator in Darth, I will bite the bullet and get a good heavy duty aftermarket one like Gary did.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

ArdWrknTrk

Re: 300 I6 to V8

Administrator

Which is why I said you'd probably want a bigger radiator than you'd use with a Windsor.
And it's not just one V-8 radiator. There's "Extra Cooling" and "Super Cooling" which show differing system capacities.

Fortunately I haven't had too much trouble keeping my truck cool.
But I am on top of fresh coolant and always use distilled water so scale and sludge aren't an issue.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

mat in tn

Re: 300 I6 to V8

familiar topic as im building one right now also. many of the things are different yet the chassis was designed around many options, so it is very doable, and you are in the right place here. many experienced truck guys. on the perches, i made my own. we run a metal fab shop along with old school auto repair. however i do have a few trucks for me to be able to get my measurements from. i installed a roller 5.0 with a modified aod and i am doing exhaust at the moment.