I think so, the stock 351w in my 95 Lightning had plenty of get up and go @ 245HP and 340 ft/lbs of TQ. 350ish HP and the associated rise in TQ would be a lot of fun.

Now granted the truck came with 4.10's, but still. Which makes me think, perhaps you should try a gear swap with that 5 speed?

Your question is not really as simple as it sounds.  Reason is that the power output of an engine that is felt when you are driving a car can not be expressed by a single number.  Instead you need to have the power curve of the engine so that you can identify the amount of power being produced at the RPMs you will be normally driving at.  For a daily driver, an engine that produces most of it's torque in the lower RPMs will feel more powerful than even a larger engine if it only makes power in the higher RPMs.

I did the swap in my Mustang.  It was a piece of cake give or take finding headeers that fit (a problem you probably won't have because you have much more volume in which to put them).  I had to make an alternator bracket but everything else pretty much swapped directly from my 28-oz 289 to my 28-oz 351.   Easy-peasy

Last edited by John Ha (2/05/2018 2:43 PM)

Gears are not really an option.  The car came with 3.00:1 gears and I already upgraded them to the 3.25:1 that I mentioned in the original post.  The T5 is a wide ratio and first gear doesn't last long before I shift to 2nd as it is now.  In is current configuration the car is really well balanced in relation to drivability and RPMs and has good power, it just doesn't set me back in the seat like the 289 in my Mustang does when I step on it.  ​(Galaxie easily weighs 1000 pounds more than my Mustang)

Rufus68 wrote:

Your question is not really as simple as it sounds.  Reason is that the power output of an engine that is felt when you are driving a car can not be expressed by a single number.  Instead you need to have the power curve of the engine so that you can identify the amount of power being produced at the RPMs you will be normally driving at.

In my case it really is that simple because basically all that is changing is the power curve is moving up.  Like I siad in the original post the engine is built with low end torque in mind and the same would be true with the 351 build.  It would be a smooth idle cam high compression, performer intake, aluminum heads.  Basically the ONLY thing changing would be the extra CI from the bigger engine.  Here is the power curves for both engines based on all the engine specs.

302


351


Thes are vurtual numbers at the flywheel and are on the high side but they paint a fairly accurate picture of the over all curve.


 

If you want performance to equal that of your 302 Mustang, I’d suggest getting the power to weight ratio about the same.  I’d use 3000 lbs for the Mustang and 4000 lbs for the Galaxie.  Although this isn’t an exact science, you’ll be close.  Also, with the same power to weight ratio, and with as light as the Mustang is in the rear (allowing the tires to spin more easily), the Galaxie may be quicker off the line.
Personally, I’m a fan of swapping the in a 351 for the 302.
 

Swap out the 302 with a 351 and don't look back!
ALTHOUGH the 351 is heavier, making the old Gal even heavier.....you are starting out with more torque/HP in stone stock condition!
Cam with more lift....more duration BUTT....wider LSA (112-114) for smooth idle... with timing optimized ignition timing and all the other HP stuff (9.5 cr......better breathing heads......"flowing" intake with 700-750cfm carb...free flowing muffs and headerz)
Your next "project" will be putting that IRS under the Old Gal!
It will "definitely" ....'set-you-back' in the seat!!
6sal6

625 cfm carb..... Might be a little under carb'ed IMO.
700 cfm minimum to make it run/idle right. 
Go out and jog around the block for me............breathing through a soda straw.
That longer stroke/bigger pistons need a lot more air/fuel than the old 302.
Gas mileage will prolly suffer with the smaller carb too
 Jus say'in!
6s6

6sally6 wrote:

Gas mileage will prolly suffer with the smaller carb too

I don't follow... can you 'splain that to me?

BobE wrote:

If you want performance to equal that of your 289 Mustang, I’d suggest getting the power to weight ratio about the same.  I’d use 3000 lbs for the Mustang and 4000 lbs for the Galaxie.  Although this isn’t an exact science, you’ll be close.  
 

Bob you hit the nail on the head!!  The whole purpose of my question was to get feedback from others that had swapped out a 302 for a 351 and to see if those swaps showed good improvement.  I was after real world experience as to weather or not that 50 extra HP would translate to noticeable power improvement in the car.  I didn't really get the type of answer that I was looking for (actual results from a similar swap) but your idea gave me some numbers I can use to help with my decision (I love match and numbers!!)

Assuming what ever engine built will get 1 HP per cubic inch AND be built to maximize low end torque:

Mustang weight to HP with 289
2500/289=  8.65:1 #/HP

Galaxie weight to HP with 302
3500/302=  11.59:1 #/HP

Galaxie weight to HP with 351
3500/351=  9.97:1 #/HP

The 351 will not get me to the same ratio I have with the Mustang, in fact it only gets me about half way there, but there is a big enough difference between the two cars so I know there will be a noticeable improvement with (half way)


Then If I do the math in reverse (galaxie weight / Mustang ratio) I can get the actual engine size I would need to have the same performance level (roughly)

3500/8.65 = 404.62 CI

To get over 400 CI I have to go with a big block or a stroker and I don't want to do either of those things so now I just need to decide if the $ to improvement ratio is worth it for the 351.







 

Hmmm... wonder if that explains these numbers from the bash this year???

My 289, T-5 with 500cfm 4v carb and 3.25:1 rear gears got 18mpg
CoupeDaddy's 5.0, T5 with 725cfm 4v carb and 3.73 rear gears got 21mpg

Raymond_B wrote:

TKOPerformance wrote:

Raymond_B wrote:

I think so, the stock 351w in my 95 Lightning had plenty of get up and go @ 245HP and 340 ft/lbs of TQ. 350ish HP and the associated rise in TQ would be a lot of fun.

Now granted the truck came with 4.10's, but still. Which makes me think, perhaps you should try a gear swap with that 5 speed?

The Lightning 351 also had GT40 heads and intake and was EFI.  It was handicapped by a peanut flat tappet cam, but it made some serious torque.  A typical 351 is going to make less torque with stock, old Windsor style heads.  1HP per cube is a good goal, but I'd consider how you plan to get there because its going to take at the very least head work, a good cam, exhaust, etc.  I do think the improvement in low speed torque will be a benefit to a heavy car, so long as you don't go trying to get more and more power, which sacrifices that low speed torque for top end.

He stated he has some aluminum heads, not sure what type, but I bet they are better than the GT40 irons. And yeah I never expected him to use the Lightning cam (hope not), but what I was illustrating is that the 351w is good for a nice TQ increase over the 302 in a comparably heavy vehicle.

With 1.94" intake valves I doubt it.  The GT40s flow very well stock, especially at lower lift.  On a performance oriented engine, even with fairly modest goals of 1HP/cube most aftermarket heads are going to move to a 2.02/1.60 valve combination.  Now in part, its because those Chevy sizes are cheapest, but on a 351 cubic inch engine you're the same displacement as a typical 350 SBC, and those valve sizes were first offered in all the stock higher performance SBC heads because they flowed better than the smaller valve heads. 
 

Daze wrote:

BobE wrote:

If you want performance to equal that of your 289 Mustang, I’d suggest getting the power to weight ratio about the same.  I’d use 3000 lbs for the Mustang and 4000 lbs for the Galaxie.  Although this isn’t an exact science, you’ll be close.  
 

Bob you hit the nail on the head!!  The whole purpose of my question was to get feedback from others that had swapped out a 302 for a 351 and to see if those swaps showed good improvement.  I was after real world experience as to weather or not that 50 extra HP would translate to noticeable power improvement in the car.  I didn't really get the type of answer that I was looking for (actual results from a similar swap) but your idea gave me some numbers I can use to help with my decision (I love match and numbers!!)

Assuming what ever engine built will get 1 HP per cubic inch AND be built to maximize low end torque:

Mustang weight to HP with 289
2500/289=  8.65:1 #/HP

Galaxie weight to HP with 302
3500/302=  11.59:1 #/HP

Galaxie weight to HP with 351
3500/351=  9.97:1 #/HP

The 351 will not get me to the same ratio I have with the Mustang, in fact it only gets me about half way there, but there is a big enough difference between the two cars so I know there will be a noticeable improvement with (half way)


Then If I do the math in reverse (galaxie weight / Mustang ratio) I can get the actual engine size I would need to have the same performance level (roughly)

3500/8.65 = 404.62 CI

To get over 400 CI I have to go with a big block or a stroker and I don't want to do either of those things so now I just need to decide if the $ to improvement ratio is worth it for the 351. 

Daze - I believe you HP values at 1HP/cubic inch is low for the engine modifications listed.  However I suspect that you're close ... all things considered, I believe the better choice is the 351.  Keep us posted.