Stroker size

https://www.google.com/search?q=400+ford+rod+length&oq=400+ford+rod+&aqs=chrome.1.69i57j0i22i30l4j0i15i22i30j0i390.10450j0j7&sourceid=chrome&ie=UTF-8



Interesting a 351C and a 400 Ford both have a 1.65 rod ratio.

I might check the math on the 460 521 and 545's ratios latter and see how they pan out.

429- 1.84, 460- 1.71, 501/514- 1.62, 521- 1.58, 545- 1.48.  Assuming rod lengths of 6.605, 6.605, 6.7, 6.8, and 6.7 respectively.

4.14/6.8=1.6425 has a nice sound to it and is almost identical to the 351C and 400 Ford Ratio.

Seems like a lot of the early strokers were built like this with BB Mopar rods.

Don Wash's Project 514 Mustang used a 4.15 crank and a 6.8 426 rods. It had the Ford MotorSport A460 heads. It was featured in the 1987 Hot Rod Ford High Performance Publication. That is the first time I saw one in print. It had a 1.639 rod ratio, quoted from the article.

Before that in the 80's the PAW 490 Gorilla Kit seemed like the big deal back then. I don't remember what rods it had and the old catalog I used to keep around for old time sake, it vanished somewhere, so I can't look. The prices in it would almost make you cry so that's probably good it's hiding.

^^^ This is just chit chat about some of the above posts not at the OP's question per say.

To the OP is you are not going with an A460 block or a D9 Block my preference would be a 4.3" Crank on a 6.8" rod.

I nearly mentioned Mopar rods but doesn't seem anyone does it anymore.  Used to be a guy at our track with a Mopar 7" or something in a very cool 70 mustang that ran well into the 10s

My father had an old paw I used stare at for hours, especially the 572 "godzilla" or whatever it was called.

I think it was Popular Hot Rodding magazine that did a BBF story way back in the early 90's where they built a 528 inch motor using A460 heads / intake, but I recall they used an offset ground factory crank and long rods from a straight six cylinder.
It's a practice that is not common anymore ever since the markets got flooded with complete stroker rotating kits.
I just remember the article had a picture of a cool 69 Torino fastback doing a hellified burnout!

http://www.riverracer.net/forums/archive/index.php/t-93236.html

I posted the period article of the marine 540 version once. It had a .140" overbore on a factory block. Pretty ballsy in my opinion but, cool none the less for back in the day. 240 Ford six cyl. rods. I am not recomending this now by any means shape or form, it is for information purposes only.

Just to add to the stroker disscussion.

Correct me please if this is wrong.

If a 6.7" rod is used with a 4.3" crank, and you go to a 4.5" crank latter, all that is required are new pistons and the new crank? LoL

PS: If it works I am not recomending it. I posted that earlier in this thread 4.3/6.8" if it were ME/MY engine.

supervel45 wrote:Just to add to the stroker disscussion.

Correct me please if this is wrong.

If a 6.7" rod is used with a 4.3" crank, and you go to a 4.5" crank latter, all that is required are new pistons and the new crank? LoL

PS: If it works I am not recomending it. I posted that earlier in this thread 4.3/6.8" if it were ME/MY engine.

Yes, same rod, new crank, and shorter piston.  Not many off the shelf pistons for 4.3 / 6.7 build, only KB hypers on summit.  Few more optoins for a 6.7 on a 4.14/4.15 crank though, inculding scj pistons, but not as many a 4.15 / 6.8 combination.  

I was considering doing a 4.14/4.15 ground crank with a 6.8 rod then going to a 4.3 crank down the road.

With a 4.15" you may not have to deck the block as much? Pay very close attention to pin heights on 460 pistons, many different ones. That may be the wrong term, but you get what I am saying. Some are just .010" to maybe .030" different. You can stack the 4.14"4.15" maybe like some of the 3.85" deals? I cannot remember all the different cuts from when I last checked on my 3.85" though but my dual valve relief Probes were a little shorter then the true single valve relief Flattops.

https://www.460ford.com/threads/460-scj-p51-pistons-499-95.166809/

More Goodness from before FaceShit got Big.

https://www.460ford.com/threads/any-resonable-priced-pistons-for-scj-heads.164160/

supervel45 wrote:http://www.riverracer.net/forums/archive/index.php/t-93236.html

I posted the period article of the marine 540 version once. It had a .140" overbore on a factory block. Pretty ballsy in my opinion but, cool none the less for back in the day. 240 Ford six cyl. rods. I am not recomending this now by any means shape or form, it is for information purposes only.

I've has 2 stock blocks that went .140" over with good wall thickness left.
One was a 507" in a street car and the other was a 490"in my dragster..
Neither were all out, balls to the wall, max effort motors.. But solid,reliable, good HP builds.

QtrWarrior wrote:

supervel45 wrote:http://www.riverracer.net/forums/archive/index.php/t-93236.html

I posted the period article of the marine 540 version once. It had a .140" overbore on a factory block. Pretty ballsy in my opinion but, cool none the less for back in the day. 240 Ford six cyl. rods. I am not recomending this now by any means shape or form, it is for information purposes only.

I've has 2 stock blocks that went .140" over with good wall thickness left.
One was a 507" in a street car and the other was a 490"in my dragster..
Neither were all out, balls to the wall, max effort motors.. But solid,reliable, good HP builds.

I actually have a set of those rods. Already have arp bolts and bronze bushings installed, re sized, shot peened. Ready to go.

stanger68 wrote:

QtrWarrior wrote:

supervel45 wrote:http://www.riverracer.net/forums/archive/index.php/t-93236.html

I posted the period article of the marine 540 version once. It had a .140" overbore on a factory block. Pretty ballsy in my opinion but, cool none the less for back in the day. 240 Ford six cyl. rods. I am not recomending this now by any means shape or form, it is for information purposes only.

I've has 2 stock blocks that went .140" over with good wall thickness left.
One was a 507" in a street car and the other was a 490"in my dragster..
Neither were all out, balls to the wall, max effort motors.. But solid,reliable, good HP builds.

I actually have a set of those rods. Already have arp bolts and bronze bushings installed, re sized, shot peened. Ready to go.

Ive heard of 460 blocks going .120 (the paw 572 i mentioned) .140 is new to me, but i suppose it boils down to how thin youre comfortable going and the potential of blowing out a cylinder.

IIRC all 240 rods are forged.  Are those 6.795 or did you have the little end moved when you bushed em?  What pin size?  Would you be interested in getting rid of those..?  Maybe ill shoot you a pm.

140 can be done on a good block. I have also seen them wear into the casting flaws of the water jacket after running for a while too.

Yes I would sell the rods. I haven’t looked at them in many years. They’re on the shelf in my closet so they shouldn’t be rusted or anything. I don’t remember specifics of dimensions.

stanger68 wrote:140 can be done on a  good block. I have also seen them wear into the casting flaws of the water jacket after running for a while too.

Yes I would sell the rods. I haven’t looked at them in many years. They’re on the shelf in my closet so they shouldn’t be rusted or anything. I don’t remember specifics of dimensions.

Been doing some digging since i posted my reply.  Two of the companies that made pistons for this application are not even in business anymore, and the other two dont have them in the catalog.  Is a shame, would be perfect for my low buck build and a good dose of old school / uniqueness.  Paying $800-900 for custom pistons, on top of grinding the crank pretty well sinks the boat.  Big sadge

Would still be awesome if someone ever wanted to build a 300 that revved to the moon. Few people out there chopping up LS heads and putting them on em, might have a chance to get a little money out of em yet.

Double post, oops

Doxnoogle wrote:

stanger68 wrote:

QtrWarrior wrote:

supervel45 wrote:http://www.riverracer.net/forums/archive/index.php/t-93236.html

I posted the period article of the marine 540 version once. It had a .140" overbore on a factory block. Pretty ballsy in my opinion but, cool none the less for back in the day. 240 Ford six cyl. rods. I am not recomending this now by any means shape or form, it is for information purposes only.

I've has 2 stock blocks that went .140" over with good wall thickness left.
One was a 507" in a street car and the other was a 490"in my dragster..
Neither were all out, balls to the wall, max effort motors.. But solid,reliable, good HP builds.

I actually have a set of those rods. Already have arp bolts and bronze bushings installed, re sized, shot peened. Ready to go.

Ive heard of 460 blocks going .120 (the paw 572 i mentioned) .140 is new to me, but i suppose it boils down to how thin youre comfortable going and the potential of blowing out a cylinder.

IIRC all 240 rods are forged.  Are those 6.795 or did you have the little end moved when you bushed em?  What pin size?  Would you be interested in getting rid of those..?  Maybe ill shoot you a pm.

I had one I ran at .140 over for 2 years before it split a cylinder wall. Had ran it at .110 for 3 years and had to bore it or start with a new block so we tried it. After it split the wall I had 8 sleeves put in it and the one that split is the only one that broke through when boring for the sleeves.

...See Post Below...

supervel45 wrote:Just to add to the stroker disscussion.

Correct me please if this is wrong.

If a 6.7" rod is used with a 4.3" crank, and you go to a 4.5" crank latter, all that is required are new pistons and the new crank? LoL

PS: If it works I am not recomending it. I posted that earlier in this thread 4.3/6.8" if it were ME/MY engine.

https://www.460ford.com/threads/stroker-combos.101546/

Sorry about that this the one I meant to quote above.

Post #4

I guess if you had a 4.3 Chine cast crank and some cheap Chine 6.8" I-Beam rods and some really fancy forged race pistons, you could get a forged 4.5"crank and 6.7" H-Beams later if you stepped up you game and re-use the Expensive Pistons. If you go with a A460 block or even a D9 latter the shorter rod does not seem so bad. "They" need to get A460 blocks out bad though.

Doxnoogle wrote:

As to bearing speed, i know historically there were lots of big blocks spinning lots of rpm.  Not to say a 2.2 journal isnt an improvement in weight, friction, oil temp, and even windage like randy said.  Still turning a 3" main at the end of the day, personally i side with the people who feel the larger rod journal and better overlap adds to rigidity and durability.  I dont want to get into a rod length debate because there are opinions all over the map and little evidence to support either side.  Plenty of great minds feel the con rod "connects the piston the the crank" and thats just about right in my book.  Going from a 6.605 to 6.7 or even 6.8 isnt going to produce much difference in rod ratio.  Youre limited by piston to crank clearance and deck height so theres just not much wiggle room for rod angle changes vs like a sbc going 5.7 to 6.2 for instance.  The rules i go by are: at least 1.5:1 ratio, generally speaking, longer rod the better without sacrificing ring pack dimensions, less side loading, more dwell after tdc, less peak piston speed, and theoretically doesnt demand as much of the head / intake.  The whole second half of that being irrelevant for the vast majority.

Rod ratio is not the MAIN reason for using a longer rod in a big block Ford.

A shorter rod pulls more of the piston further out of the bottom of the bore which promotes more piston rock and shorter ring life no matter what the ring pack dimensions are.
The later production blocks have longer bores than the earlier internal balanced engines and the A460 has even a bit longer bore.

In a race engine which is coming apart often for a freshen-up, it doesn't matter so much.

There are some production engines where the rod ratio is near 1.48/1 but, they run for miles and miles without piston ring distress because the piston remains almost fully in the bore at bottom dead center.

No matter the rod length, the PEAK piston speed will be, (for all intensive purposes), the same, (happens farther down the bore for a longer rod, about 75 degrees past top dead center), and is controlled by the stroke length. Longer rods do have less piston speed near TDC at the top of the bore but, have a shorter dwell time and faster piston speed than a short rod near the bottom of the bore. The average all evens out.

supervel45 wrote:

supervel45 wrote:Just to add to the stroker disscussion.

Correct me please if this is wrong.

If a 6.7" rod is used with a 4.3" crank, and you go to a 4.5" crank latter, all that is required are new pistons and the new crank? LoL

PS: If it works I am not recomending it. I posted that earlier in this thread 4.3/6.8" if it were ME/MY engine.

https://www.460ford.com/threads/stroker-combos.101546/

Sorry about that this the one I meant to quote above.

Post #4

I guess if you had a 4.3 Chine cast crank and some cheap Chine 6.8" I-Beam rods and some really fancy forged race pistons, you could get a forged 4.5"crank and 6.7" H-Beams later if you stepped up you game and re-use the Expensive Pistons. If you go with a A460 block or even a D9 latter the shorter rod does not seem so bad.  "They" need to get A460 blocks out bad though.

Thanks for the link good read IMO!!

rmcomprandy wrote:

Doxnoogle wrote:

As to bearing speed, i know historically there were lots of big blocks spinning lots of rpm.  Not to say a 2.2 journal isnt an improvement in weight, friction, oil temp, and even windage like randy said.  Still turning a 3" main at the end of the day, personally i side with the people who feel the larger rod journal and better overlap adds to rigidity and durability.  I dont want to get into a rod length debate because there are opinions all over the map and little evidence to support either side.  Plenty of great minds feel the con rod "connects the piston the the crank" and thats just about right in my book.  Going from a 6.605 to 6.7 or even 6.8 isnt going to produce much difference in rod ratio.  Youre limited by piston to crank clearance and deck height so theres just not much wiggle room for rod angle changes vs like a sbc going 5.7 to 6.2 for instance.  The rules i go by are: at least 1.5:1 ratio, generally speaking, longer rod the better without sacrificing ring pack dimensions, less side loading, more dwell after tdc, less peak piston speed, and theoretically doesnt demand as much of the head / intake.  The whole second half of that being irrelevant for the vast majority.

Rod ratio is not the MAIN reason for using a longer rod in a big block Ford.

A shorter rod pulls more of the piston further out of the bottom of the bore which promotes more piston rock and shorter ring life no matter what the ring pack dimensions are.
The later production blocks have longer bores than the earlier internal balanced engines and the A460 has even a bit longer bore.

In a race engine which is coming apart often for a freshen-up, it doesn't matter so much.

There are some production engines where the rod ratio is near 1.48/1 but, they run for miles and miles without piston ring distress because the piston remains almost fully in the bore at bottom dead center.

No matter the rod length, the PEAK piston speed will be, (for all intensive purposes), the same, (happens farther down the bore for a longer rod, about 75 degrees past top dead center), and is controlled by the stroke length. Longer rods do have less piston speed near TDC at the top of the bore but, have a shorter dwell time and faster piston speed than a short rod near the bottom of the bore. The average all evens out.

I agree, which is one reason im not keen to build a 545, or a 347 or 427w for that matter (fairlane is going to be a 393 when i get around to it). Doable, sure, lots of people do it without problems even, sure. Are they known to have ring issues and burn oil, also yes. I dont like how tight the ring pack is in those engines, and how short the piston is. If youre right on the verge of what you think the piston is good for, a longer rod very well could be the diff between a reliable engine and launching a piston. Without getting into the math of it all, mostly because i would have to look it up to reliably know what im talking about, but the g forces and rod load is exponential as rpm is increased. Small differences there can make big changes. I have no experience personally with this so im kinda talking out of my arse as it were. Avg piston speed however, is of course a given with any rod combo, and is just stroke x rpm, and the one people mistakenly look at most often. End of the day, its just my preference to keep the engine over-square, and stay as close to or over a 1.6:1 rod ratio as possible. Theres other benefits which are a given for such a combination too, which i feel out weigh the extra 24 cubes.

You're welcome Mark. I don't know if you caught the date on the link, 16 years ago, and the debate was around long before that.

^^^ The OP is going to hate me for this maybe but for serious Stroker Power I believe we really need the A460 blocks so we can get the 4.5 to 4.6" bores to go with the 4.3" and 4.5" cranks with the serious cylinder heads. SCJ heads with a 4.3" stroke is fine and makes nice HP on a good budget with a factory block though. They do have a cutoff point in the HP department.

https://www.youtube.com/watch?v=dIrvPfrnXjM

Doxnoogle wrote:

stanger68 wrote:…Yes I would sell the (240) rods….

…Two of the companies that made pistons for this application are not even in business anymore, and the other two dont have them in the catalog…. Paying $800-900 for custom pistons, on top of grinding the crank pretty well sinks the boat.

This is still very financially do-able given current pricing for commercially available stroker kit combos: I’m currently working on a very similar OEM 460 stroker crank combo that will use a shelf H-beam rod and can even use a shelf stroker piston (with a single change).  The result will be a nodular iron cast crank stroker kit with H-beam rods and forged pistons for about the same price as an offshore stroker kit, at least as strong as the cast crank offshore stroker kits (if not stronger) and as good a rod ratio as the similarly spec’d offshore stroker kits.

The current-day, cookie-cutter stroker kits have not been updated for about thirty years now, and this new recipe addresses that.  I’ve got a similarly stroked forged crank version in the works, too. My targeted goal is as follows: assuming both the new and old designs are the same displacement and horsepower, the new design will easily out-accelerate the antiquated design down the track.

Details to follow at a later date.

^^^ That's great Paul. I am glad to hear you are working on that. Way too much vintage iron going to scrap in my opinion is my reason though. If it runs better then the "cookie cutter" stuff that's an excellent bonus.