Posted By: RockChip
RB rods in short deck ??? - 02/08/13 04:42 AM
Does anyone make a piston for stock stroke 400 with a 6.760 rod?
RB rods in short deck ???
Posted By: 10.90 Racer
Re: RB rods in short deck ??? - 02/08/13 04:48 AM
Quote:
Does anyone make a piston for stock stroke 400 with a 6.760 rod?
Why would you want a long rod????
Posted By: Winchester 73
Re: RB rods in short deck ??? - 02/08/13 05:58 AM
iev heard that 460 ford rebuilder cast pistons are where to look
Posted By: Streetwize
Re: RB rods in short deck ??? - 02/08/13 02:21 PM
PM member MoPork, he has a long rod 383 combo that revs really nice. Not sure who made his slugs but Ray Barton did his short block.
That said, from my experience Diamond will pretty much make you anything you want for a pretty reasonable fee.
That said, from my experience Diamond will pretty much make you anything you want for a pretty reasonable fee.
Posted By: HEMIFRED
Re: RB rods in short deck ??? - 02/08/13 02:55 PM
NOTES FROM A VERY SHARP MEMBER
http://victorylibrary.com/mopar/rod-tech-c.htm
http://victorylibrary.com/mopar/rod-tech-c.htm
Quote:
Planning a 383 Motor
This engine is generally overlooked in selecting a high-performance project. The motor has an excellent bore to stroke ratio: 1.26-1 (similar to 327 SBC, better than 340). The short stroke allows high RPM without destructive piston speed (7100 RPM = 4000 ft./min., the accepted safe limit for piston stress). The large bore permits big valves (2.14 intake, 1.81 exhaust).
A potential method of increasing peak power is to substitute the longer 440 6.768 (LY) rods for the original B 6.358 rods on the original crank. This has the following effects:
» Increases the rod ratio (n) from 1.884-1 to 2.005-1
» Reduces the piston compression distance to about 1.525 for a useful weight savings
» Slightly reduces piston acceleration
This should allow an advantage in peak power. For a start in piston selection, take a look at the KB224 for BBC: flat top, CD = 1.52 (just below zero deck), and .990 pin for more weight savings and moderate cost. There may also be possibles for the 400 (4.34 bore), but not discovered yet. Ideas?
Posted By: gregsdart
Re: RB rods in short deck ??? - 02/08/13 03:02 PM
What do you have in mind? There are some good choices if you are willing to offset grind a stock crank and use chevy rods. You can get 426 cubes very cheaply out of a 400 with a stroked 383 crank.
Posted By: MRMOPAR622
Re: RB rods in short deck ??? - 02/08/13 06:01 PM
You can use a 4.15 crank,6.57 rods with a 1.30 cr-height pistons that combo works real well in a low deck.
Posted By: YYZ
Re: RB rods in short deck ??? - 02/08/13 06:34 PM
Diamond & Ross both make a shelf piston with 1.320" compression height that will work nicely in a B-engine with 3.75" stroke and 6.760" rods
Posted By: JohnRR
Re: RB rods in short deck ??? - 02/08/13 06:38 PM
Quote:
You can use a 4.15 crank,6.57 rods with a 1.30 cr-height pistons that combo works real well in a low deck.
The 1.320 Ch piston that is available will work with 3.75 , 3.9 and 4.25 strokes with just a rod change.
'
I'll actually ANSWER the OP question There isn't a shelf stock piston but as mentioned above any of the manufactures will make you one , EXCEPT KB ... You need a piston about 1.520
Diamond actually lists one for a 383 but not a 400 ??? odd ...
Posted By: AndyF
Re: RB rods in short deck ??? - 02/08/13 09:20 PM
We used Hemi rods with a forged 383 crankshaft in a 400 engine with a shelf piston. That worked but these days I'd just buy a semi-custom piston rather than jury rig something.
I also doubt that I'd ever use a Mopar connecting rod again. Might as well use a Chevy 6.70 or a 6.80 rod. The Chevy rods are less expensive and tend to be higher quality since they are built in much higher volumes. You do have to grind the crank journal down. Another benefit is that with the Chevy rod you have a much wider selection of bearings to pick from including various undersizes and chamfer options.
I also doubt that I'd ever use a Mopar connecting rod again. Might as well use a Chevy 6.70 or a 6.80 rod. The Chevy rods are less expensive and tend to be higher quality since they are built in much higher volumes. You do have to grind the crank journal down. Another benefit is that with the Chevy rod you have a much wider selection of bearings to pick from including various undersizes and chamfer options.
Posted By: ProSport
Re: RB rods in short deck ??? - 02/08/13 11:06 PM
Quote:Quote:
Does anyone make a piston for stock stroke 400 with a 6.760 rod?
Why would you want a long rod????
Why not?
Best engine I've ever owned was my low deck 451, zero deck flat tops, 440 crank 6.76 440 rods, Eddy heads, 590 purple shaft in at 104. Ran 9.90's at 3050 pounds through the mufflers. Very streetable too.
Posted By: Dean_Kuzluzski
Re: RB rods in short deck ??? - 02/09/13 12:42 AM
Quote:Quote:Quote:
Does anyone make a piston for stock stroke 400 with a 6.760 rod?
Why would you want a long rod????
Why not?
Best engine I've ever owned was my low deck 451, zero deck flat tops, 440 crank 6.76 440 rods, Eddy heads, 590 purple shaft in at 104. Ran 9.90's at 3050 pounds through the mufflers. Very streetable too.
While you're 451 was quite outstanding............
I think the point others are trying to make is that the 383/400 already has a better rod-to-stroke ratio and anything more is beyond a point of valid results/return. Meaning, not worth the cost of custom pistons & rods for the marginal gain.
There's no cubes gained like the long rod 400/451 combo, just less piston/rod angularity and a longer dwell time at TDC. All of which is debatable to many on this board.
Good topic though, I'd like to see a build to see a roller cam'd 383 hammer'd out on a dyno.
Posted By: gregsdart
Re: RB rods in short deck ??? - 02/09/13 01:11 AM
Rockchip, where are ya?
Anyway, Ross makes a 4.375 bore (400 block) piston in 1.421 compression height to fit .990 pins. There are lots of low priced H beam rods made with 2.200 rod bearings, and 6.8 long. Put the whole deal together with the 383 crank ground to about 3.52 stroke, and you have about the cheapest good stroker combo IMHO. Total compression height works out to 9.981, or close to perfect. It gives you an off the shelf rod, piston, and the only extra machine work is offset grinding the rod journals. For those that get their pantys in a bunch over rod ratios (not pointed at any one in particular!)
the rod ratio comes out at 1.932, almost ideal.
Another good thing about this combo- price the difference between the 2.200 race rod bearings and the mopar 2.375 bearings. I paid $180 for my last set of race bearings (-.001) for my Mopar sized crank.
Anyway, Ross makes a 4.375 bore (400 block) piston in 1.421 compression height to fit .990 pins. There are lots of low priced H beam rods made with 2.200 rod bearings, and 6.8 long. Put the whole deal together with the 383 crank ground to about 3.52 stroke, and you have about the cheapest good stroker combo IMHO. Total compression height works out to 9.981, or close to perfect. It gives you an off the shelf rod, piston, and the only extra machine work is offset grinding the rod journals. For those that get their pantys in a bunch over rod ratios (not pointed at any one in particular!)
the rod ratio comes out at 1.932, almost ideal.Another good thing about this combo- price the difference between the 2.200 race rod bearings and the mopar 2.375 bearings. I paid $180 for my last set of race bearings (-.001) for my Mopar sized crank.
Posted By: WO23Coronet
Re: RB rods in short deck ??? - 02/09/13 01:15 AM
Although the power benefits are debateable, wouldn't a long rod be easier on the bottom end and pistons due less side loading and less rod angularity? Probably help stave off cap walk a little longer as well
Posted By: JohnRR
Re: RB rods in short deck ??? - 02/09/13 01:55 AM
Quote:
Rockchip, where are ya?
Anyway, Ross makes a 4.375 bore (400 block) piston in 1.421 compression height to fit .990 pins. There are lots of low priced H beam rods made with 2.200 rod bearings, and 6.8 long. Put the whole deal together with the 383 crank ground to about 3.52 stroke, and you have about the cheapest good stroker combo IMHO. Total compression height works out to 9.981, or close to perfect. It gives you an off the shelf rod, piston, and the only extra machine work is offset grinding the rod journals. For those that get their pantys in a bunch over rod ratios (not pointed at any one in particular!)
Another good thing about this combo- price the difference between the 2.200 race rod bearings and the mopar 2.375 bearings. I paid $180 for my last set of race bearings (-.001) for my Mopar sized crank.
If there is that CH piston he could use the Hemi spec 6.860 rod on the 383 crank and save the cost of grinding the crank.
Posted By: gregsdart
Re: RB rods in short deck ??? - 02/09/13 04:35 AM
Quote:Quote:
Rockchip, where are ya?
Anyway, Ross makes a 4.375 bore (400 block) piston in 1.421 compression height to fit .990 pins. There are lots of low priced H beam rods made with 2.200 rod bearings, and 6.8 long. Put the whole deal together with the 383 crank ground to about 3.52 stroke, and you have about the cheapest good stroker combo IMHO. Total compression height works out to 9.981, or close to perfect. It gives you an off the shelf rod, piston, and the only extra machine work is offset grinding the rod journals. For those that get their pantys in a bunch over rod ratios (not pointed at any one in particular!)
Another good thing about this combo- price the difference between the 2.200 race rod bearings and the mopar 2.375 bearings. I paid $180 for my last set of race bearings (-.001) for my Mopar sized crank.
If there is that CH piston he could use the Hemi spec 6.860 rod on the 383 crank and saze the cost of grinding the crank
True, but the down side is a VERY heavy rod,more bob weight, and the crank may need work anyway. Plus you lose the cubes, and the 424 to 426 cube deal should be a real winner with small port heads.
Posted By: AndyF
Re: RB rods in short deck ??? - 02/09/13 05:10 PM
Quote:Quote:Quote:Quote:
Does anyone make a piston for stock stroke 400 with a 6.760 rod?
Why would you want a long rod????
Why not?
Best engine I've ever owned was my low deck 451, zero deck flat tops, 440 crank 6.76 440 rods, Eddy heads, 590 purple shaft in at 104. Ran 9.90's at 3050 pounds through the mufflers. Very streetable too.
While you're 451 was quite outstanding............
I think the point others are trying to make is that the 383/400 already has a better rod-to-stroke ratio and anything more is beyond a point of valid results/return. Meaning, not worth the cost of custom pistons & rods for the marginal gain.
There's no cubes gained like the long rod 400/451 combo, just less piston/rod angularity and a longer dwell time at TDC. All of which is debatable to many on this board.
Good topic though, I'd like to see a build to see a roller cam'd 383 hammer'd out on a dyno.
I spent a fair amount of time on the dyno with that little 400 engine. Stock 383 forged crank, Hemi rods, and as much compression as we could get with the short stroke. It made pretty good power for a small engine and moved the car down the track really well. I thought it was a great combo.
Posted By: JohnRR
Re: RB rods in short deck ??? - 02/10/13 05:52 PM
Quote:Quote:Quote:Quote:Quote:
Does anyone make a piston for stock stroke 400 with a 6.760 rod?
Why would you want a long rod????
Why not?
Best engine I've ever owned was my low deck 451, zero deck flat tops, 440 crank 6.76 440 rods, Eddy heads, 590 purple shaft in at 104. Ran 9.90's at 3050 pounds through the mufflers. Very streetable too.
While you're 451 was quite outstanding............
I think the point others are trying to make is that the 383/400 already has a better rod-to-stroke ratio and anything more is beyond a point of valid results/return. Meaning, not worth the cost of custom pistons & rods for the marginal gain.
There's no cubes gained like the long rod 400/451 combo, just less piston/rod angularity and a longer dwell time at TDC. All of which is debatable to many on this board.
Good topic though, I'd like to see a build to see a roller cam'd 383 hammer'd out on a dyno.
I spent a fair amount of time on the dyno with that little 400 engine. Stock 383 forged crank, Hemi rods, and as much compression as we could get with the short stroke. It made pretty good power for a small engine and moved the car down the track really well. I thought it was a great combo.
Andy that was a good build , the bad thing is that rod is no longer in existence , it was the Manley sportsmaster 6.965 rod if I remember right , after you did that build I was going to do my 383 that way , rods couldn't be found .
Posted By: gregsdart
Re: RB rods in short deck ??? - 02/10/13 08:54 PM
Quote:
Although the power benefits are debateable, wouldn't a long rod be easier on the bottom end and pistons due less side loading and less rod angularity? Probably help stave off cap walk a little longer as well
Unless a guy is really pushing the motor, I don't see cap walk as a problem.