Are they all offset bolt patterns? My CSI starter from the old 350 appears to be missing a hole for a bolt to go into. :lol: :lol

 

To the best of my recollection, all small blocks have three holes drilled and tapped for starter mounting. The two holes directly 90* to the crank are for 153 toothed flywheels. The two that are offset, as you say, are for 168 toothed flywheels. The two patterns share a hole, so it only takes three. All 400s came with 168 toothed flywheels, therefore they use the offset set of holes. I believe the third hole should be there, though. I could go downstairs and uncover a block or two to double check. Some aftermarket starters have four holes, all in line, so you can move the starter nearer or farther from the crank to accomodate either tooth count with only the in line set of block holes. Good luck, and...

RACE ON!!!

 

Good question, I had one 400-509 casting block with parallel holes and one 509 block with diagonal holes. If you are buying a new starter just buy the one for the block you choose.

 

You can only do that if you are willing to let the starter bolt pattern dictate the flywheel use. See my first post.Both blocks had only two holes? I can't imagine a 400 block that wouldn't accommodate the offset (diagonal) pattern, because that's what it takes for the 168 toothed flywheel the 400s used.

This discussion and my curiosity got the better of me. I just went downstairs and unwrapped a 400 cid, "509", 2 bolt main, 2 freeze plug block. This one has three starter mounting holes.

RACE ON!!!

 

Interesting! My 509 block has three holes.

 

My engine will be back out in 2 weeks, I will look at the hole pattern then.

All I know is the first 509 block I bought,,, bolted up to my 1985 vette starter no problems,,, the second block I bought I had to drill a hole to use my 1985 vette starter. AND I used a 153 tooth flywheel both times,


[Modified by ld85, 9:40 AM 11/29/2003]

 

All of this, makes sense. The '85 Corvette has a 153 toothed flywheel and because of that, it uses the inline starter bolt pattern. With an inline bolt pattern you would HAVE to use a 153 tooth flywheel (both times) because that is what it is for. All 400s used the 168 toothed flywheel, and used the offset bolt pattern starter. Your first block HAS to have three starter mounting holes. Because A) It used the offset pattern in it's origional application, and B) Your inline patterned starter bolted on. The second block was drilled for the offset pattern, only which is all 400s actually used. Hence, you had to drill a hole to use the inline pattern starter. All production 400s used the 168 tooth flwheel, which automatically dictates the offset starter mounting. Have you ever noticed how hard it is to buy an unbalanced 153 tooth flywheel? That's because Chevy never used one. It is a specialty market item, only. I'll bet big bucks, you'll find an offset bolt pattern (three holes) on that block when it comes back. Good luck, and...

RACE ON!!!

PS. At least on the 350 and 400 blocks I have had experience with, a two bolt starter pad is a rarity. I don't think I've ever seen one. Obviously, your second block was one.

 

Getting back to Jack71's origional question. All 400s use the offset bolt pattern. Most are drilled to accommodate either starter. It sounds like you have a block like ID85's second block. You have two choices, as I see it. One, is to drill your block as ID85 did. Or two, convert to a 168 tooth flexplate. Good luck, and...

RACE ON!!!

 

Well, I have a 168 tooth flexplate on there now. So I guess I just need a new starter. Damn, guess its time to EBay out a CSI mini starter...

 

You will love the header & oil pan bolt clearance as a result of the mini starter, I will never own a style other than the mini starter having seen how well it fits and it is made for higher HP engines.

 

Jack71,

I can't get back to your origional post from here. Did you say you have a mini starter, now? You almost have to, if your starter uses inline mounting holes with a 168 tooth flexplate. It would be the one I described with 4 holes. All 4 in a line and 2 used with the small flexplate and the other two for the larger. I don't know if what you need, is made. You could go to a stock style starter with the offset pattern or you may end up drilling a hole. Good luck, and...

RACE ON!!!

 

My 400 (817 casting) only has two diagonal holes for the starter. Since it's still on the stand, i'm probably going to drill the additional hole. The bigger problem is finding an externally balanced 153 tooth flexplate. LPE sells one, but they want $200 for it :sad:

 

Ralph,
I thought you had solved that problem. Have you called Summit and Jegs? The older catalog I have handy at the moment, doesn't show your flexplate, but I'm sure I've seen them. What are you planning to use for a starter? The most economical route to take would be a 168T flexplate and a stock style, offset patterned starter. That way you could use a Summit, $56.00 plate and not have to drill and tap the extra hole. If you have a good, stock, inline bolt pattern, starter, you can convert it by simply changing the nose piece. Good luck, and...

RACE ON!!!