Swapping to a 351

MATTKNIGHT · 06-10-2003, 08:24 AM

Well, I have been having F.I. probs with my 95 5.0. I kicked around the idea of carbing the thing, but then I decided otherwise. I have a 1978 ford bronco with a 351 M in it. I think this might be the answer to my prob. I am going to doa little swap, reducing my bronco to a 5 liter. What do you guys think about a 351 M. Also, where can I look for performance goodies like heads for the thing? Anyone done a swap similar to this that can give me advice?? Would appreciate input, thanx ahead of time.

WADS56 · 06-10-2003, 08:31 AM

I am not positive but I think the 351m has about no aftermarket suport at all. Even the 351c has limited aftermarket parts, but there 4v heads are kick *** and I don't THINK they will fit on a 351m. The 351m's came in trucks and that is what they are good for not a mustang.
Wade

Stang_ROTY · 06-10-2003, 11:26 AM

I agree. THe 351M I believe is a Marine application, someone correct me if I'm wrong. Either way, you need to find a Winsdor if you want to save many headaches.

BilLster · 06-10-2003, 02:19 PM

351 M is for Modified 400 , cross between clevland and big block.

heavy and hard to find performace parts find a 351 W 71-74 block 69-70 have diffrent deck heights and are a little diffrent but stong if you get a complete one. heads block crank ect.

87BOSS351C · 06-10-2003, 03:07 PM

Don't waste your time with a 351M (the M doesn't stand for anything). Any cleveland head will fit it and some other c parts. You can put on the 4V C heads but you have to run a 4V C intake and spacers (the M and 400 have a more than 1" taller deck height than the C) and you will have to have custom made headers. The cam and timing chain and gears and cover and oil pan will all interchange between the M and C. Rods, pistons, crank and push rods are all different. Also, your bronco (78) will have the crappy smog 2V heads. These are basically the same as a 2V C head but it has a big bump in the exhaust port. Also the flywheel and clutch from the stang won't work (the 351M uses 28.x oz balance). And the M motor mounts are 351M and 400 only bastards. The bellhousing pattern is the same as the 429/460 so your tranny won't even bolt up.

The 351M/400 is great for a 4x4 cause it has good low end torque and not much else. They are part of the 335 series engine family which started with the 351C in '70 (400 in '71, 351M in '75 to replace the 351C which ended in '74). The 429/460's are the 385 series. Really Ford never called them Big Blocks and Small Blocks back at that time. The 335 series and 385 series will interchange distributers and rocker arms.

You would be looking at way more work than gain with that swap.

Fox Body · 06-10-2003, 03:21 PM

351M/400 = 351 modified 400

87BOSS351C · 06-10-2003, 03:55 PM

No it doesn't. Per Ford the M has no meaning other than to tell the three 351's apart. Although I do admit that I call them Modifieds as well.

06-10-2003, 08:24 AM	#1
MATTKNIGHT Registered Member Join Date: Jun 2003 Location: MOUNTAINHOME, IDAHO Posts: 20	Swapping to a 351 Well, I have been having F.I. probs with my 95 5.0. I kicked around the idea of carbing the thing, but then I decided otherwise. I have a 1978 ford bronco with a 351 M in it. I think this might be the answer to my prob. I am going to doa little swap, reducing my bronco to a 5 liter. What do you guys think about a 351 M. Also, where can I look for performance goodies like heads for the thing? Anyone done a swap similar to this that can give me advice?? Would appreciate input, thanx ahead of time. __________________ MATT KNIGHT 1995 5.0, msd 6al, msd coil, bbk longtubes, bbk offroad, 2 chamber flows, power tower shift, 98 gt wheels

06-10-2003, 08:31 AM	#2
WADS56 gear banger Join Date: Aug 2000 Location: CHICAGO Posts: 1,144	I am not positive but I think the 351m has about no aftermarket suport at all. Even the 351c has limited aftermarket parts, but there 4v heads are kick *** and I don't THINK they will fit on a 351m. The 351m's came in trucks and that is what they are good for not a mustang. Wade __________________ 79 Hatch: NA 347, Stage 2 Canfield Heads, Victor JR. Intake, Blueprinted Holley 750 HP, Solid Roller Cam, Shooting for 10's on motor 93 LX: Tremec, dual friction clutch, fms flywheel, Hedman shorties, O/R H-pipe Ricer hater's club member #49

06-10-2003, 11:26 AM	#3
Stang_ROTY Registered Member Join Date: Feb 2001 Location: Berkshire County - Massachusetts Posts: 735	I agree. THe 351M I believe is a Marine application, someone correct me if I'm wrong. Either way, you need to find a Winsdor if you want to save many headaches. __________________ Red 1993 GT Street Machine Best E.T. - 12.41/Best MPH = 108 Engine is a 1969 351 block w/393 stroker kit. Dynamic Roller Myte C4, 8 pt cage. Edlebrock Performer heads and Victor Jr. EFI, FRPP 30lb injectors & Cartech fuel system. MSD ignition. Sothside Machine bars & Sub-frames, adj. upper's, 3.73's, Koni rear shocks, much more

06-10-2003, 02:19 PM	#4
BilLster Registered Member Join Date: Oct 2000 Location: Ontario canada Posts: 446	351 M is for Modified 400 , cross between clevland and big block. heavy and hard to find performace parts find a 351 W 71-74 block 69-70 have diffrent deck heights and are a little diffrent but stong if you get a complete one. heads block crank ect. __________________ 89 with 331 t3'/t4 hybrids. upr Suspention worked out finnaly . 9.89 144 mph .

06-10-2003, 03:07 PM	#5
87BOSS351C Registered Member Join Date: Sep 2002 Location: Midland, Michigan Posts: 92	Don't waste your time with a 351M (the M doesn't stand for anything). Any cleveland head will fit it and some other c parts. You can put on the 4V C heads but you have to run a 4V C intake and spacers (the M and 400 have a more than 1" taller deck height than the C) and you will have to have custom made headers. The cam and timing chain and gears and cover and oil pan will all interchange between the M and C. Rods, pistons, crank and push rods are all different. Also, your bronco (78) will have the crappy smog 2V heads. These are basically the same as a 2V C head but it has a big bump in the exhaust port. Also the flywheel and clutch from the stang won't work (the 351M uses 28.x oz balance). And the M motor mounts are 351M and 400 only bastards. The bellhousing pattern is the same as the 429/460 so your tranny won't even bolt up. The 351M/400 is great for a 4x4 cause it has good low end torque and not much else. They are part of the 335 series engine family which started with the 351C in '70 (400 in '71, 351M in '75 to replace the 351C which ended in '74). The 429/460's are the 385 series. Really Ford never called them Big Blocks and Small Blocks back at that time. The 335 series and 385 series will interchange distributers and rocker arms. You would be looking at way more work than gain with that swap. __________________ Black '87 LX 5.0 5 spd T-top with 450hp '71 351 Cleveland 4V, C6 tranny, "and some other stuff" Rice Haters Club Member #124

06-10-2003, 03:21 PM	#6
Fox Body Mustang Maniac Join Date: Sep 2000 Location: GA, U.S.A Posts: 2,266	351M/400 = 351 modified 400 __________________ 351W-powered 1979 Ford Mustang Ghia notchback '79 Video @ Idle Stock 5.8L under 4" cowl 'glass hood, C4 w/ Transgo shift kit, Holley 750 cfm, Edelbrock Performer RPM intake; Fluidyne Al radiator, Flexalite 175 electric fan, 1 5/8" MAC shorty headers, FRPP Al driveshaft; S&W 6-point cage; 2.5" Off road H-pipe, 2-chamber Flowmasters, 8.8" Rear w/ 3.55s; Weld wheels (15x6;15x8), Front: 225/60/15, Rear: 275/50/15 Nitto NT 555R Drag Radials; 14 x 4” K&N X-stream air filter. '92 GT (5-speed) Small In Car Video Stock 5.0L, 2-chamber Flowmasters, MAC CAI, Tri-Ax, Al pedals... "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body

06-10-2003, 03:55 PM	#7
87BOSS351C Registered Member Join Date: Sep 2002 Location: Midland, Michigan Posts: 92	No it doesn't. Per Ford the M has no meaning other than to tell the three 351's apart. Although I do admit that I call them Modifieds as well. __________________ Black '87 LX 5.0 5 spd T-top with 450hp '71 351 Cleveland 4V, C6 tranny, "and some other stuff" Rice Haters Club Member #124

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
swapping yolk out, how to..???	I KNOW IM SLOW	Windsor Power	0	05-17-2003 11:50 AM
What could I gain by swapping to longtubes?	Grn92LX	Windsor Power	2	05-29-2002 07:50 PM
is this cam worth swapping?	85muffstang	Windsor Power	2	02-26-2001 02:08 AM
Hi i am swapping a 302 for a 460 any advice?	Headless	Classic Mustangs	2	05-03-2000 06:45 AM
411 on swapping 4cl to 302?	mattblackstang	Small Ponies	0	11-29-1999 01:11 PM