same or different 391 & 390

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Jan 24, 2006 | 03:00 PM

topgunn

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Joined: Nov 2005

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From: columbia river gorge

same or different 391 & 390

my first time on the chat. i have a vintage bluebird motorhome with a 391 FORD hooked to an allison 6 speed auto. i want to get MORE power so i need specs on the 390, i have on the 391. has anybody put any kind of fuel injection on a 390/391. i hope to turbo it and it would be easier with injection.

any info would be appreciated
herb gunn

Last edited by IB Tim; Jan 24, 2006 at 03:06 PM.

Jan 24, 2006 | 03:05 PM

IB Tim

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Jan 24, 2006 | 03:58 PM

bryyce62

Fleet Mechanic

Joined: Nov 2004

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From: Northern CA

390 & 391 are like dog & cat. One is an industrial truck engine (hence the motorhome application) one is a auto engine. I'm sure the rest of the gang will be by shortly, but It'll take quite a bit of work for you to get where you want to go with that project of yours.
Good luck,
b62

Jan 24, 2006 | 04:36 PM

krewat

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From: Long Island USA

The 391 is an FT engine, the 390 is an FE engine.

The bellhousing is the same, but you would need a 390 flywheel, and possibly a different clutch (most likely). And 390 exhaust manifolds or headers.

Problem is, the engine mounts are probably on the front of the engine, using the timing cover, and nothing like that exists for the FE. What series truck did they use for the base? You could use the 391 timing cover with the 391 crankshaft, keep the 391 flywheel, possibly update the pistons to a higher compression, and use 390 heads, intake, etc. Even with the stock 391 block, you could probably bolt on 390 heads and intake and be done with it - however, I have no idea what the compression would be (what are the chamber sizes for FT heads vs FE heads like D2TE/C8AE ???).

Were you planning on unbolting the 391 and bolting in a 390 from somewhere?

Jan 24, 2006 | 05:28 PM

FFR428

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Joined: Oct 2004

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From: CT

The 391's have a forged steel crank which is nice compared to the 390's nodular iron. Just keep in mind as mentioned the crank snout/ timing cover as the 391 crank has a larger OD snout and timing cover seal than the std FE cranks. Also the 391 FT heads use a smaller ex valve and stem and the heads have large chambers 80-81cc's. The heat crossover on the heads and intake are in the center vs the rear on the std FE heads and intake. The 391's use a HD block casting and have been found to be the same as the 428 CJ in some cases. The "428" identifiers can be found inside some of the 391 blocks depending on the year.

G.

Jan 24, 2006 | 06:08 PM

ford390gashog

Fleet Owner

Joined: Jan 2004

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From: Brentwood,CA

when did they put a 6 speed behind them? what year is it?

Jan 24, 2006 | 09:46 PM

gtex

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Posts: 6,175

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From: Texas

AN FT motor might be a good candidate for force induction. It's tough as a brick chithouse and it already has low compression. As said above, maybe step up to some good flowing FE heads and intake. A blower is probably easier as Turbos seem to be completely custom setups for FEs with little or no aftermarket support.