Posted By: bobs69
Stroke a 273?? - 01/16/10 12:59 AM
Anybody ever stroke a 273 ?? 
Stroke a 273??
Posted By: Supercuda
Re: Stroke a 273?? - 01/16/10 01:07 AM
Can't possibly imagine a situation where anyone would want a stroked 273. unless it was to say they did it. Small bore/long stroke isn't a good combo for HP.
Posted By: DAYCLONA
Re: Stroke a 273?? - 01/16/10 01:11 AM
No,...but there was this girl.....
Seriously, the bore is just too small to warrant the kind of work and money your looking at,.....start with a 340/360, you'll be cubes ahead
Seriously, the bore is just too small to warrant the kind of work and money your looking at,.....start with a 340/360, you'll be cubes ahead
Posted By: dave571
Re: Stroke a 273?? - 01/16/10 03:24 AM
FWIW I know of guys who have stroked 318's with reasonable results. The bore is pretty small.
For me, I'd get a 360 block to start with.
Cheaper and bigger.
For me, I'd get a 360 block to start with.
Cheaper and bigger.
Posted By: bobs69
Re: Stroke a 273?? - 01/16/10 03:41 AM
I was just trying to do something different. I am getting the 273 complete with transmission for free and wanting to put it in my 66 pickup and i do take it to the track sometime. 
Posted By: 340dart4spd
Re: Stroke a 273?? - 01/16/10 03:55 AM
How about this Option..
MOTOR TRAXX MOPAR TECHLINE
by Bob Doty
360 Stroker Motors
The 360 is an excellent engine as it stands. It shares the common rod length with the 340, the basic block, heads, manifolds, etc. The crankshaft has a larger main journal diameter, but the same rod journal size as all small blocks. My personal performance preference is the 360 over the 340. The primary reason is the longer stroke. 3.31 vs. 3.58. This allows more bottom end torque, the ability to use more camshaft and still be streetable, and less gear in the rearend. I have built identical engines on the 340 block and the 360 block, and the 360 will be about 2 to 5 tenths quicker in the quarter mile. It simply does not have to work as hard. This sometimes does not sit well with the legendary 340 diehards. The 340 is an excellent engine, but I leave them for the restoration crowd. The 360 is cheap to acquire, plentiful, and tough. The cast crank is basically bulletproof and will work forever to 6500 RPM.
The 360 may be stroked in a couple of ways. I have built two stroker 360 engines and they were awesome performers. Each was built in a different manner. The standard configuration is a .040 over 360 with an aftermarket crankshaft with about a 3.79 stroke. They are available from 2 or 3 different sources including Mopar Performance. They must have the 360 main journal size. (there are also the same cranks for the 340, with the smaller main journal size.) Once you acquire the crank, you must have custom pistons....because of the longer stroke....otherwise the pistons will strike the head at TDC. Remember that only half the stroke increase is at TDC and the other half is at BDC. You could consider milling the piston approximately .105, but would have to consider the thickness of the top of the piston.
Another method is the welded up crank, then offset ground to get the stroke increase you desire. This method is currently popular for the 440 to get to the 498 displacement size. It is also somewhat costly.
The third method that I have used to build my first 360 stroker back in 79 or 80 was to cut the rod journal down and offset grind it. We cut it down to 2.00 small block Chevrolet rod journal size and offset ground it to get the stroke increase. I used 6.00 length Chevrolet rods (Carillo) and Ross Pistons. We bored the early (71) 360 block .080 and ended up at a calculated 392 cubic inches. It was a screamer for about 10 races (oval track) and then the crank flange broke off. I built the twin to it with the same results. (harmonics).
The 3.79 stroke with a .040 overbore is 383 cubic inches. The early 360 blocks (71 to 73) will accept an oversize of .080. This is due to the fact that the 340 and 360 shared the production tooling until the demise of the 340 in 1973. The standard bore size of the 340 was 4.040 inches and the 360 was 4.000. You can overbore the 360 to the 4.040 size and still have the material to go to a .040 over 340, or 4.080 inches. There have been successful bore jobs to 4.100 on the early blocks. That would be a .060 over 340.
The bottom line is yes....it can be done. Is it cost effective with the crank work and the custom pistons? Probably not. A .060 over 360 is 372 cubic inches. Eleven cubic inches is not worth $2000 to me.
There are custom cranks for the 340 and 360 on the market that result in 406 cubic inches. They all cost about the same, so if you are going to go......go first class!!
Thanks for the time.
MOTOR TRAXX MOPAR TECHLINE
by Bob Doty
360 Stroker Motors
The 360 is an excellent engine as it stands. It shares the common rod length with the 340, the basic block, heads, manifolds, etc. The crankshaft has a larger main journal diameter, but the same rod journal size as all small blocks. My personal performance preference is the 360 over the 340. The primary reason is the longer stroke. 3.31 vs. 3.58. This allows more bottom end torque, the ability to use more camshaft and still be streetable, and less gear in the rearend. I have built identical engines on the 340 block and the 360 block, and the 360 will be about 2 to 5 tenths quicker in the quarter mile. It simply does not have to work as hard. This sometimes does not sit well with the legendary 340 diehards. The 340 is an excellent engine, but I leave them for the restoration crowd. The 360 is cheap to acquire, plentiful, and tough. The cast crank is basically bulletproof and will work forever to 6500 RPM.
The 360 may be stroked in a couple of ways. I have built two stroker 360 engines and they were awesome performers. Each was built in a different manner. The standard configuration is a .040 over 360 with an aftermarket crankshaft with about a 3.79 stroke. They are available from 2 or 3 different sources including Mopar Performance. They must have the 360 main journal size. (there are also the same cranks for the 340, with the smaller main journal size.) Once you acquire the crank, you must have custom pistons....because of the longer stroke....otherwise the pistons will strike the head at TDC. Remember that only half the stroke increase is at TDC and the other half is at BDC. You could consider milling the piston approximately .105, but would have to consider the thickness of the top of the piston.
Another method is the welded up crank, then offset ground to get the stroke increase you desire. This method is currently popular for the 440 to get to the 498 displacement size. It is also somewhat costly.
The third method that I have used to build my first 360 stroker back in 79 or 80 was to cut the rod journal down and offset grind it. We cut it down to 2.00 small block Chevrolet rod journal size and offset ground it to get the stroke increase. I used 6.00 length Chevrolet rods (Carillo) and Ross Pistons. We bored the early (71) 360 block .080 and ended up at a calculated 392 cubic inches. It was a screamer for about 10 races (oval track) and then the crank flange broke off. I built the twin to it with the same results. (harmonics).
The 3.79 stroke with a .040 overbore is 383 cubic inches. The early 360 blocks (71 to 73) will accept an oversize of .080. This is due to the fact that the 340 and 360 shared the production tooling until the demise of the 340 in 1973. The standard bore size of the 340 was 4.040 inches and the 360 was 4.000. You can overbore the 360 to the 4.040 size and still have the material to go to a .040 over 340, or 4.080 inches. There have been successful bore jobs to 4.100 on the early blocks. That would be a .060 over 340.
The bottom line is yes....it can be done. Is it cost effective with the crank work and the custom pistons? Probably not. A .060 over 360 is 372 cubic inches. Eleven cubic inches is not worth $2000 to me.
There are custom cranks for the 340 and 360 on the market that result in 406 cubic inches. They all cost about the same, so if you are going to go......go first class!!
Thanks for the time.
Posted By: 68KillerBee
Re: Stroke a 273?? - 01/16/10 10:25 AM
turbo 
Posted By: 72swinger360
Re: Stroke a 273?? - 01/16/10 10:19 PM
Quote:
turbo
I'm with you. Build a 7000+ RPM twin turbo screamer!!!
Posted By: Shaker223
Re: Stroke a 273?? - 01/17/10 02:29 AM
Quote:Quote:
turbo
I'm with you. Build a 7000+ RPM twin turbo screamer!!!
X3
Posted By: patrick
Re: Stroke a 273?? - 01/18/10 12:28 PM
Quote:
FWIW I know of guys who have stroked 318's with reasonable results. The bore is pretty small.
For me, I'd get a 360 block to start with.
Cheaper and bigger.
the bore on a 318 is bigger than the 5.3 & 5.7 LSx GM motors...it's only .090 smaller than a 360.
the 273 is only 3.625" bore, 3/8" smaller than a 360....
where would you find reasonable cost stroker pistons?
Posted By: hunterstroble
Re: Stroke a 273?? - 01/18/10 02:46 PM
if you want to be different find a solid lifter, dual quad 350 ci b engine. =)
Posted By: BradD
Re: Stroke a 273?? - 01/18/10 09:50 PM
If I had an original 273 car but wanted more power without adders, I would grind a 360 crank's mains.
Then find/buy a piston to fit.
Then find/buy a piston to fit.
Posted By: DaytonaTurbo
Re: Stroke a 273?? - 01/18/10 09:55 PM
For the price you'll pay for those custom pistons, that 273 doesn't sound all that good for free. I think a 273 with a blower sitting on top of it would be cool. Should make good mpg, have some good punch to it and definitely an A+ in cool factor. 
Posted By: HotRodDave
Re: Stroke a 273?? - 01/19/10 03:00 AM
a 3.58 stroke will not hardly give you any more cubes but with the 2bbl pistons and a really thick head gasket you could end up with good quench and compression for not too terible amount of $$$. It would be a 302 at .030 over but not as big a bore, however it would still be a bigger bore than stroke so it could be made to turn some RPM to get some HP. A serious effort on the original heads I would guess could serve up to 325 or so HP.
If you go to a 4 inch crank you will make it undersquare and still not make much more than the 325 or so HP but TQ could be halfway to respectable. You would still be smaller than a 340 (338 actually)if you went with a .030 over bore and custom pistons would definately be required.
Even if you went all the way to a 4.125 crank it would still only be 348 inches and the head flow would still be restricted by the bore and 1hp per cube would require a max effort job. To save money you might be able to find a freezplug to work for a piston.
If you go to a 4 inch crank you will make it undersquare and still not make much more than the 325 or so HP but TQ could be halfway to respectable. You would still be smaller than a 340 (338 actually)if you went with a .030 over bore and custom pistons would definately be required.
Even if you went all the way to a 4.125 crank it would still only be 348 inches and the head flow would still be restricted by the bore and 1hp per cube would require a max effort job. To save money you might be able to find a freezplug to work for a piston.