Small vs. Large block

[Ford68Pony]

Well this is pretty much my first mustang and I've learned quite a bit but one thing I recently decided to get some info on the difference between a big and a small block engine. I've seen a couple of pages that says it's just the parts but I was wondering from a mechanical standpoint some of the differences? Do they use the same mounts in a classic mustang? Do they perform about the same? Does one require more maintenance or have more problems than the other? Any of you more experienced tinker-ers "mind" brining more knowledge to this brain of mine? Yes the small punn was intended.

 

[zookeeper]

The basic difference is obviously the physical size of the engine. But as far as living with one on a day to day basis, here's a few things to consider. Both engines are very reliable. Anyone who's ever worked on a big block Mustang can tell you, it's a complete pain in the rear. There simply is no room for even the simplest maintenance. Since Mustangs are unibody cars, bigger motors mean bigger stresses, which in turn means problems with shock towers cracking sooner than they would with a small block. Big blocks installed in cars not originally equipped with them have a higher resale value, unless the original motor was something like a 271hp 289. The bigger the motor, the worse the mileage. Big block cars share virtually nothing with small block cars, and the swap parts are spendy, plan on getting very familiar with ebay and your checkbook. Also, you might want to change your sig, unless someone swapped it in there, your car (or any other vintage Mustang) doesn't have a V6.

 

[LMan]

If you going to do that conversion, I strongly suggest you use a Windsor engine (289, 302, 351, 302-based stroker, etc). Good fit, aftermarket is strong, parts are plentiful, and can be built very powerfully.

 

[Ford68Pony]

Info

Thanks for the info there Zoo... Thanks for pointing out the V6 Error... It was an inline 6 instead. Looks like sticking with a small block is the way to go for someone like myself when it comes time to swap out engines.

Lman, conversion was completed back in '04. I used a 302 I found in an 84 mustang (it was an origional block from a 68 galaxy). Conversion went pretty smoothly until we tried to fire up the engine and found out it had a 351 firing order. Whoever rebuilt the car put on some newer parts.

I've included a picture to show the engine right after I put it in. The only dif now than in the pic is I went to a v-belt instead of keep

 

[LMan]

ok, sorry I misread your .sig..I thought you were planning the conversion now.

I would go no larger than a 351 block.

 

[Ford68Pony]

Thanks LMAN...

 

[tylerrocks]

I smoked a 454 equiped pickup yesterday in my 64 with a built 306. YEEEAAAAHHH. smallblocks kickass.

Tyler

 

[RedGTvert]

Anyone who's ever worked on a big block Mustang can tell you, it's a complete pain in the rear. There simply is no room for even the simplest maintenance.

You aren't kidding. Try changing plugs on a '70 428CJ.

 

[brin0357]

Or headers. Those are such a pain on big block cars. Cool thing to do is use later shock towers on earlier cars to clear big blocks. I dont see any point in building andything over a windsor block unless your full out drag racing, then go 460 or FE.

 

[Sicarius428]

There are a bunch of quirks with Big blocks. What are your goals first? FEs for one have overheating issues. Granted they run hot to begin with but definately wern't meant for the modern urban environment. At long stoplights you can watch the temp gauge move. Motor mounts... even the shock tower bracing is different(If you go BB definately get the shock tower bracing). Just about anything a big block can do can be achieved with a stroked 351 but I do have to say that a factory Big Block casting can handle more power than a factory small block casting. Small block handling is greatly improved by loosing the couple hundred pounds off the front end but by replacing the cast FE heads and intake you can bring the weight down to a full cast windsor weight(FE cast intake weights like 70 lbs... probably land small planes on it too). For me spark plugs don't seem to be much of an issue but the headers were a serious pain to get in. Parts are easier to find and typically cheaper for a small block. Things do break or need replacing time to time. The big block's biggest perk is the torque. There is really no feeling to describe it. Its awesome.
Kevin

 

[Max Power]

You aren't kidding. Try changing plugs on a '70 428CJ.

Been there. I found that a 1 inch extension is a huge help. That and ratchet heads that swivel front and back.

I ditched the headers. 428s are torque motors, and manifolds were fine for torque.

My 393 stroker is faster.

 

[zookeeper]

Several years ago, a friend had a '69 Shelby GT500. He bought the car from the original owner with very few miles (under 20K). Since he's the meticulous type, he wanted to swap plugs, but since the car was an A/C car from California (940 miles of smog tubing covering the engine) he couldn't even see the plugs! So he took it to a Ford dealer and they told him that the motor would have to come partway out to swap plugs, and as such he would be charged the same as a motor swap. Needless to say, he drove the car as is until he sold it a few years later. Like the dumbass I am, I passed up the chance to buy the car for $10,500. If I remember right, the year was about '88 or so and the car had under 80K miles on it.

 

[HHStang]

I'm for the big block (and I'm manning up to be flamed ).

Nothing says old school better than opening that hood and seeing a gigantic engine. Buy a 89-93 5.0 if you want a small block. (The BBF) looks better, it sounds better and you can gain cheap, reliable horsepower (429-460). Did we talk about torque yet? The 429/460 is a monster at low rpms (where most of spend our time driving on the street).

Don't get me wrong. I loved my S trimmed 97 Cobra, I love my 05 GT, but nothing can replace either my 72 429 or 67 Procharged 460. BIG BLOCKS RULE.....

My 2 cents...

 

[65ShelbyClone]

1.)Do they use the same mounts in a classic mustang?
2.)Do they perform about the same? Does one require more maintenance or have more problems than the other?

1.) No. Big blocks use their own mounts.
2.) Nope. Big blocks often make more power than small and nearly always make more more torque. No more maintenance, no more problerms.

 

[zookeeper]

I'm for the big block (and I'm manning up to be flamed ).

Nothing says old school better than opening that hood and seeing a gigantic engine. Buy a 89-93 5.0 if you want a small block. (The BBF) looks better, it sounds better and you can gain cheap, reliable horsepower (429-460). Did we talk about torque yet? The 429/460 is a monster at low rpms (where most of spend our time driving on the street).

Don't get me wrong. I loved my S trimmed 97 Cobra, I love my 05 GT, but nothing can replace either my 72 429 or 67 Procharged 460. BIG BLOCKS RULE.....

My 2 cents...

Heh, I know prevailing wisdom says that small blocks are the way to go, and to a point, I agree. After all I have one by choice and I think they're great motors. But, HHStang, is right, there ain't nothing like cubes. A few years ago, my wife entered her '69 427 'vette in the local car show in our hometown. Since we had a party to go to, we had to leave the car and return in the afternoon to pick it up. We took our '88 5.0 powered GT down to get it and I drove the Corvette home. We both got caught at the front of a stop light, and she whacked the throttle of the Mustang while we sat at the light. I know the '88 Mustang may not be the fastest car on the planet, but it's pretty darn quick. Anyway once the light changed, I let her get away about a car length or so, then stomped the gas of the Corvette. She had her foot to the floor of the Mustang and was getting ready to shift when I went by her mid way thru first in the Corvette, I ran it up to 60 or so, then backed out of it and continued home. We laughed about it later and she asked me why the Corvette was so much faster, even though it was older, heavier and such and the Mustang is pretty quick and much easier to drive. I told her that as much as I love small block Fords, there's just no substitue for cubic inches. But for me, it just wasn't worth the extra hassle of fitting my '68 to the big block.

 

[65ShelbyClone]

Buy a 89-93 5.0 if you want a small block.

Just to make things easier for parts hunters, the '87-95 5.0 HOs are all the same .......except that some time in mid to late 1992 the switch was made from forged pistons to hypereutectic. The '96+ Explorer 5.0 shortblocks are also the same way. Sometime in '97 they switched the heads from GT-40s(standard smallblock) to GT-40Ps with a different plug location which often needs different headers.