To answer your direct question, the rod length will affect rod angelarity. How that affects clearance at cam and pan rail depends on the size and shape of the rod big end. So without doing an actual ***embly with your specific cam and rods I don't see how you can predict. Rod length also affects piston speed. A shorter rod improves cylinder scavenging. For your mild usage I would order the 5.7" rod balanced ***embly and don't look back. But in either case you will need to mock up and check clearances.
Basically if you are buying the same rod with only a change in length, it should make no difference. They are going to be identical on the big end. The purpose of the article I posted is to show that there are different configuretions of the rod ends, so there is no one answer that all 5,7 rods are going to clear better than all 6.0 rods. Its all about whether you have a bolt and nut sticking down. All will clear with some clearancing, but its better to select one that doesn't have that nut protruding. You also have to be aware that those that have a rod bolt will have a "head" on the bolt that protrudes up enough to sometimes hit your cam. That requires dis***embly and grinding the edge of the bolt head to clear. Then you just shot your engine balance and weakened the bolt. I'm sure **** can provide you with a better rod that doesn't have a head on a bolt but rather a capscrew inserted from the bottom for not that much more expense. Its worth it in the long run. Also, a 6" rod tends to produce less rocking by the piston and helps prevent cylinder to piston wear. Since you apparently plan to have the machine shop ***emble your engine, you may spend more money on ***embly and dis***embly than the difference in rod costs. You might look at that #5 rod in the attachment I posted. I beam with capscrew and its from ****.
That is another excellent article by the late, great Marlon Davis. He kept me a Hot Rod magazine subscriber thru some of lame years..
ekimneirbo, that rod looks exactly like the rod in the rotating ***embly kit the **** quoted. fwiw, in the last couple of days i've talked with two machinists that both said, all else being equal the shorter rod will have more clearance than the longer rod, or at least that was their experience.
The journal overlap on a small journal 383 will be scary There is a reason chevy kept increasing journal size as the stroke increased. a 2.3" main and 2" rod journal and a 3.75 stroke leaves .275 overlap. A 400 was the smallest SB overlap @ .500 . My guess that is why there weren't any small journal 327 cast cranks.
I understand what you are saying , but on the other hand cast 400 mains have been cut down for years to be put in 350 blocks. I am just curious now ..... Take a junk 400 crank and cut the mains to 2.30 for mock up. I'm thinking a good steel crank cut to 2.30 wouldn't be a problem in a hot street car. still thinking about rod to block clearance on a 327 block .... But now inquiring minds wanna know
Just gotta think back to our hot rod roots when guys were running flatties on nitro with 3 main bearings....
I used to see cast 283 cranks broken between the main and rod journals and they had .650 overlap not .275
First I need to apologize for giving you bad info. I have been fooling around with the newer LS engines and Cadillac engines for the last 15 years or so, and my "old timers" disease has let my smallblock memory recede somewhat. I forgot that the 400 Chevy used a 5.565 rod. What I should have been saying was to use a 5.7 rod rather than a 5.565 rod..........instead of use a 6.000 rod rather than a 5.7. What I was meaning was to use the longer rod which is a 5.7 and is also what your machinists have told you. The main point was "use a longer rod". A 6.000 rod will not be a good choice because it will move the wristpin so far up in the piston that it will affect the rings.........so thats not a good choice. Like I say, I knew what I meant to say, but said it incorrectly. So my apologies. As for the statement that a different length rod will provide more block clearance than a similarly configured rod with a different length. Can't see that. If the big end of a rod is shaped the same and swinging thru the same arc, I see no reason one will provide more clearance than another. (I been wrong before) There could be a very minor difference in the angle of the rod at that point, but I don't think its enough to make any real difference. Maybe a few thousandths. Anyway, here is a diagram for you to look at. I would install the crank, cam and rods using some old bearings. Then rotate it on your workbench and check the clearances yourself before taking it to a machine shop. You can clearance the block with a die grinder, just go slowly. You will learn a lot by trying this yourself. You don't have to torque everything, just put the old bearing in it and see what you get. Then when it goes to the machine shop, you know you have sufficient clearance. There is a limit as to how much time the machine shop will spend checking cam clearance ($$$), so give it a try.
I have built a ton of 383s , not my favorite combo but but people seem to like em. I have built the cheepo ones using cut down 400 cranks and 400 rods= the easy way. I have built em with cut down 400 cranks and factory 5.7 rods with the rod bolts ground for clearance so they wouldn't hit the cam. Also used small base circle cams. I have built them with factory 5.7 rods using ARP 4.3 V6 rod bolts for cam clearance. The best way in my book for a street engine is an aftermarket steel crank with 5.7 cap screw stroker rods , You still need to double check everything but it is very straight forward. Like I said before Iv'e never done it with a small journal block but back in the day guys were using 283 blocks and stroking them and boring them to 350 inches. Was some really sketchy **** but they did it.
The Jalopy Journal
