I'm just geting into working on engines now and I'm buying a 302 V8 5.0L engine form my friends dad's 1988 Mercury Grand Marquis and I was wondering if it is possible to bore the 302 block into a 351 and if so whats the highest cubic in. are possible from a 302? My plan is to drop a that engine into a 1966 mustang. I'd like to work on this motor in my college engine class. I'd like to get as much power as possible out of the 302... Hope someone can help me out on this one

 

The 351 and the 302 both have the same bore: 4.00". It's the stroke and deck height of the engines that are different. The 302 has a 3.00" stroke with a 8.20" deck height while the 351 has a 3.50" stroke with a 9.50" deck height. You increase the size of the 302 with a longer stroke crank (stroker) and, yes, there are kits to put 3.25" stroke (331ci) or 3.40" (347ci) or 3.50" (357ci) stroke cranks (all with +.030" overbore).

 

The bore is the same at 4.00 inchs. I think the hishest you can go on a 302 is to 347. The 351 has a higher deck height.

 

Dang I type to slow.

 

I've never seen a production block 302 built bigger than 347 ci, and these kits use pistons that move the wrist pin up into the oil ring. Many 347 engines are oil burners as a result, though there are some good ones.

I suspect that an earlier writer mistook standard stroke .030" overbore 351W engines, which are 357 ci, for a long stroker 302.

If you use one of the good race blocks that are out there, your 302 can be bored into the .120" over range, or even a little more and then you can get more than 347 ci.

-Matthew

 

Uh, no. Lunati makes a kit that uses a 3.50" stroke crank, 5.4" rods and pistons with the extremely short pin height needed. In fact, custom machined 351C cranks (for 3.40"-3.50" strokers) have been around for a long time. The first one I ever saw was in 1970.

 

I'd be very interested in a part number for the alleged lunati kit. The closest to the kit you mentioned that I can find are their kits EA31 through EA33, all of which are advertised as "350 ci", but are actually 347 ci kits using a 3.425" stroker crank.

-Matthew

 

I don't know the part number of the kit, but a buildup of one was done in Popular Hotrodding's Engine Master series of magazines. There was also a link posted on this website to another website that outlined the machining necessary to put a 351C crank in a 302 block (along with putting Chevy rods in a 289, building a 357/408 Clevor and other stuff).

 

Why don't you just get a 351W block and stroke it? You can make 393 ci easily with cheap parts that has a much better stroke/rod ratio than these 302 based strokers. By the time you buy a stroker kit, you could have already bought a 351 block and the 3.85" stroke crank for it that makes it a 393, and still have money left over to go towards heads, intake and ignition. Not to mention, the 351 blocks are much stronger, and will last at least twice as long as any 347 stroker will. I have never seen a daily driven 347 stroker, and never seen one still alive after 50k miles.

 

Most of the new kits do not intersect the ring.

 

A 351 is a stroked 302 and a 302 is a stroked 289 simply speaking. If this is for a 1966 Mustang why not be original and put the 289 in it. The GT350 had 289 HIPOs and they put out 306 HP

 

1. 351 is not a stroked 302.
2.302 is dimensionally the same as a 289 and more abundant.
3.You can get a factory roller 302 for cheap and it will make more power than a flat tappet 289.
4.The hipo 289 was a solid lift cam and only made 271 crank hp, and that was on the old sae ratings, which would have been higher than todays numbers.

 

The 1966 Mustang GT350 put out 306 hp. I got that from an actual published book but think what you want. You also have to consider that the hipo 289 put in the GT350 werent just stock 289 hipos and were often "Shelbized" And I'm not saying a 289 can have more power than a 302. Im saying that why put a 302 in a 1966 when that wasnt a powertrain option. If it was my Mustang Id want to keep it as original as possible. And I stand corrected a 351 is not a stroked 302

 

Did I say it didn't?
Why not?
Is he building a concourse class restored vehicle? If he were I don't think he would be modifying for power.

Inarius, if I remember correctly your 88 merc 302 might be a roller cam motor. If so I would go with a decent street grind and add a good carbed intake and exhaust and go from there. It should make good power. If you want to get wild it'll cost you, but you have a good starting point.