Boy, now I am confused. Several years ago, one of the monthly hot rod mags (Popular Hot Rodding, I think) did an article called "The Engine Chevy Should Have Built" (this is at least close). Their theory was rather than stroking the 327 crank to 3.48", they should have stayed with the 3.25" crank , gone to a big bore and the longest rod possible. In this article they used a Ford 6.20" rod to get a 1.9:1 rod/stroke ratio) and a compression ratio of about 11:1. The cam was a mild street cam and a carburator. The resulting 350 (short stroke/big bore) made 400 hp and NO detonation on 87 octane. Their conclusion was long rods resist detonation and make good power.

 

You mentioned that the 400 isn't a special problem and I agree providing you use your stock length rods. Where there can be a potential issue is when you swap in 5.7 or 6.0 inch rods. As you stated in one of your posts...it is not an issue of actual rod length but which rod bolt and the 5.7 and 6.0 have longer bolts than the stock 400 rod. I saw that you were thumping on LT4-CE and actually what he wrote is not incorrect. With a 5.7 and 6.0 rod it is likely you will have to grind the rod bolt or run a small base circle camshaft. He did NOT say the reason you will have to grind the rods is because of the rod length. I have several 406 engines with both 5.7 and 6 inch rods and both engines required that we remove some material off the rod bolts.

 

What I am saying, or meant to say, if I wasn't clear, is that there isn't anything unique to the 400 (on the subject of rod clearance), that doesn't apply to all Gen I small blocks with a 3.75" stroke. It's the same problem with a 383.

Actually, he did.
I have no doubt. The bolt head is higher on those rods than the 5.565", 400 rods. Did the 6" rods require substantially more grinding than the 5.7"? The 5.7" rod is closer in length to Chevy's 3.75" stroke rod (5.7-5.565 = 1.35) than the 6" rod is to the 5.7" (6.00-5.7=.300). If the bolt head to camshaft interference is due to the angle change as a result in the rod length difference, one would expect the 6" rod to require more than twice the grinding of the 5.7" rod.

RACE ON!!!

 

I knew I had this somewhere......a good illustration of the subject:

 

Correct! I have the same illustraition in my Chevrolet Power Catalog.

RACE ON!!!

 

CFI-EFI,
The place our exchange ended up is not healty and I apologize for being vague in some of my posts. I certainly never intended to discount what you posted. I am sorry you took me posting what I have been told to be a disrespect of your knowledge and research. It sounds like both of us operated under similar guidance on the topic, and you took an extra step in doing additional research. All I did was post information bases on what I have been taught, right or wrong. The power of the forum is the vast array of people and experiences here. I looked back through and I DID do a poor job of leaving the door open for dialog between us. What I was seeking in the first place was information you ultimately posted and that was what you researched and to that I am sincerely thankful as I don't profess to know anywhere near all there is to know about this stuff. And I am glad that among all the forum members, most things we seek can be learned from one member or another.

I am done with this thread as it seems the technical information that was sought has been given the guy with the original post. The exchanged between you and I went beyond the topic, which was not my intent and based on the past posts I've seen from you (which have been great stuff) I guess you weren't hoping for this to end up how it did. So, again, I apologize. I didn't do a very good job of expressing my understanding and phrasing it in a way that opened dialog.

 

I like the way it seems to be ending, NOW. I too, often have problems writing, what is in my head in a manner that is understood by all. Sometimes I skip lightly over things *I* consider basic, and that can leave confusion in those not so indoctrinated. Sometimes I get very frustrated at responses I get that don't seem to relate to what I posted or repeat the question I just answered. Also, as in the rod to cam clearance question, I have trouble accepting the answer, "because". If I can't "see" it, I have trouble accepting it. I could never "see" the angle change as being enough to cause the interference. THAT is what sparked my further research.

Maybe like I suggested earlier, we should slice apart some con rods, and...

RACE ON!!!

 

After reading this discussion I feel like I wimped out when choosing 5.7 vs.6.0 I bought the GM 3.8 crank so after looking at as much info as I could figured the differance was minimal for a street sometimes track car and bought the GM 5.7 383 PM rods that they use with that crank. They have studs rather than bolts and come pre ground off for cam clearance. I just got them and they look like good quality made in USA pieces, Plus a good price from my parts guy made it a little easier. I was amazed that amount of rods available today for the small block Chev. haven't built a motor since the 70's I just hope these rods are strong enoug for some track use
Ike

 

Got a little more info than I was looking for but solved the question.I too was overwhelmed by the options available and was prepared to spend the money if I could see a tangible result.
As I am only building a hard street / strip motor for weekend use and trips I will use a 5.7 that gives adequate clearance on the cam.
Thanks for the replies.Didn't intend to stir up such a debate.

 

Interesting discussion! The illustration put up by caboboy made it perfectly clear for me along with CFI's note about the different location of the rod bolt on the 400 rod. What I have gained is that by using a rod with cap screws instead of bolts with a head creates the clearance needed. The H beam rods by Scat or Eagle should eliminate any interferance regardless of length. It also seems that the rod length in our discussion doesn't make enough difference to feel in the seat of your pants. Thanks fellas!