Can a 300 six be stroked to 4.500" stroke (340ci), is there enuff clearance between the pan rails, crank and cam, cylinder bore and rods, crank and block, rods and block.

 

It probably could, but why? It would cost at least a couple thousand bucks to do it, plus it would make the rod ratio even more miserable, greatly increase piston side loading, make the airflow discrepancies even more pronounced, etc. There are more efficient ways to spend the money on a 300. There is really only one performance related reasons to build a stroker: The power capability of the engine requires new crank, rods, and pistons to be purchased anyway.

 

silver streak is right with all of the theory. Besides can you even get a stroker crank for a 300 or would you have to offset grind a stock crank. If that is the case then this greatly weekens the structural integrity of the stock crank.

 

Just a thought about more torqe, how long are the rods in a 300 six? Skat makes stroker cranks. the engine I got came from a 93' UPS truck with 15,000 miles it is a HD motor so it has a plenty strong bottom end.

 

I think clifford performance used to make stroker cranks, but I bet you can't rev them very high....I don't have any exp. with them.

 

As I recall the 300 has pretty short rods relative to its stroke. I think a stroked 300 would be great. What if you could get a 5 inch stroke. Would max out at a low 3000 rpm like a diesel.

 

uhmmmm...lets see. 300 six 4.5" stroke 340ci, ported heads, RV cam, maybe a SC or turbo, redline 4,000-4,500 RPM, 500+ ftlb of torqe, the best part... out running a cheby SS454 truck with your 6 banger

 

I can do that already. At least for the first half of the track.

I wouldn't recommend offset grinding a 300 crank, HD steel part or not. The rod journals are only 2.12" in original trim. Adding an 1/8" of stroke would reduce that to 2", which would probably allow you to use SBC bearings. That would only add about 10ci over a stock crank, but the stress on the crank and bearings would increase considerably.

If I remember correctly the rod ratio on the 300 is just over 1.5 in stock form. 1.5 is generally considered the limit for a true street engine. You could probably keep it over 1.5 with custom rods and pistons, but there's that money thing again. $500 for a set of custom steel rods would go a long ways towards more effective mods. There is a chance that an off the shelf 302 or 351 piston would work for this, so custom pistons might not be required.

Even if this all works out and you can do it you will still be conducting an experiment that could result in engine failure. It would suck to go through all that work and spend all that money only to watch it go boom because of an unforeseen and undetectable problem. Everytime I try something new with my truck I toe the line and wonder if it's going to live. It isn't a pleasant feeling.

 

Seems I once read about a process whereby extra material was welded onto one side of the rod journal and cut from the other, resulting in the same size journal but ofset for a longer stroke. Obviously this would be a very delicate operation and probably costly. Furthermore, these jobs apparently came loose at times with dramatic effect on the track.

 

If i'm going to stroke it i'll get a crower crank.... I wonder if ARAO will make a head for a six.

 

If you want a good head for the 6 find a pair of aluminum heads for a 302, cut one cylinder off of each and have them welded back together to fit the six. The bore spacing, bolt pattern etc. are the same on both engines, they just have 2 too few cylinders on one bank of a 302. This will put the intake on the driver's side instead of the passenger's. Some 1" aluminum plate should make nice addaptors to allow the use of off the shelf 300 intake and exhaust components. You might also need to work on coolant passages a little bit to make it work well. Even with all the little things needing attention this would still be cheaper than a custom head. Ideally you could find a pair of heads at a swap meet that are broken on one end. You could probably pick them up for scrap metal prices and get some use out of them.

 

I never thought of useing 302 heads i'll think on that.