BBc old bow tie block

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67 Nova
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BBc old bow tie block

Post by 67 Nova » Wed Mar 14, 2018 11:20 am

I have an old Bow Tie that's been sitting for years.It's an old Pro Stock block. A few years ago the shop sent it out for pressure testing and full check over. Can back fine BUT now it's missing the main caps!

It's a straight cap block and from may past photos, the caps that were on it looked like regular production cast caps, like an LS6 cap? The inner bolts are rounded shoulders, 3 raised letters, stampings and and arrow for front?

Now I need ALL 5 caps, hardware is there just missing the caps. I've got a few recommendations to just reuse the OEM style factory caps. Couple even said they have had good luck with these off eBay:

https://www.ebay.com/itm/Chevy-BBC-454- ... yV&vxp=mtr

Being a machinist I really can't see those eBay caps being any worse then a cast cap that was there?

Any input is appreciated

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Re: BBc old bow tie block

Post by pdq67 » Wed Mar 14, 2018 12:47 pm

I guess that I would be all over the shop that, "lost/still has", the stock main caps!!

I did a favor for a guy that ended up giving me my worn out SJ 327 block I made my junk301 out of. It was missing one main cap..
Anyway, I had a small fit and then went to the local salvage yard, "iron pile/motor pile", looking for another cap to no avail.

Ended up that 4 months later one Sat. morning the guy he got the block from showed up with the cap!

All was good.

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Re: BBc old bow tie block

Post by SupStk » Wed Mar 14, 2018 1:04 pm

For the front four on a BBC those caps would probably work. Now you need to find a rear cap.
I've gotten some of their (pro-comp) SBC caps that were a mess. The steps were rough machined and registers weren't correct. To fix 'em required more work than they were worth. Still sitting on the shelf in the back room.
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Re: BBc old bow tie block

Post by 67 Nova » Wed Mar 14, 2018 1:45 pm

Thanks guys. Ya just not sure about the one posted. I do have a 3 axis Cinci milling machine, just figured buy those would take some of the work out of it for me.

Ya there is a bunch of issues with the shop missing my caps, and others peoples as well.

As was told about these, made in the USA ones:

http://www.jegs.com/i/PRW/228/1745403/10002/-1

Rear main would just end up being standard BBc cap

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Re: BBc old bow tie block

Post by MTENGINES » Wed Mar 14, 2018 3:06 pm

Pro Gram Engineering makes rear caps.

Competition products has their own which are nice look like a pro gram cap.

http://www.competitionproducts.com/mobi ... qlx84FlBAg

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Re: BBc old bow tie block

Post by 67 Nova » Wed Mar 14, 2018 3:14 pm

The one from Competition Products are made Howards.

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Re: BBc old bow tie block

Post by ProPower engines » Wed Mar 14, 2018 5:41 pm

Cipco industries sells a couple different main caps including the rear main cap.
Same quality as program just less costly and usually in stock ready to ship same day. the last times I have called program they were out of sm blk caps as well as bbc.
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Re: BBc old bow tie block

Post by Krooser » Wed Mar 14, 2018 9:11 pm

67 Nova wrote:
Wed Mar 14, 2018 3:14 pm
The one from Competition Products are made Howards.
Same company....
Last place in the B-main is better than anyplace in the grandstands...

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Re: BBc old bow tie block

Post by CharlieB53 » Thu Mar 15, 2018 9:23 am

Even if the shop came up with a set of caps how could you be sure they are THE correct set? Unless you have engraved a mark on them you couldn't.

Get another set and have them fitted.

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Re: BBc old bow tie block

Post by 67 Nova » Thu Mar 15, 2018 11:40 am

CharlieB53 wrote:
Thu Mar 15, 2018 9:23 am
Get another set and have them fitted.
That is what I'm doing. But no one seems to know if the old Bow Tie Block used the same caps as OEM BBc, like LS6? They "look" the same off the blocks I've seen, sq registrars and rounded inner bolt bosses. Just wondering if they were cast from a better material?

So IF the original one that were with my Bow Tie MK IV block are the same as normal BBc LS6 caps, I could look at them as there are "take-offs" there. IF there not the same, I can look at the aftermarkets that are out there. I'm hearing pretty good with the PRW's and hear that the PC can use some touch-ups.

FYI I'm personally leaning towards the PRW's unless I hear some bad thing, that so far I haven't.

Thanks, John

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Re: BBc old bow tie block

Post by Dave Koehler » Thu Mar 15, 2018 1:03 pm

I don't see how you have any choice but to go aftermarket caps and a line bore.
Finding an oem cap that actually lines up with a different block correctly is a Unicorn hunt.
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Re: BBc old bow tie block

Post by 67 Nova » Fri Mar 16, 2018 10:45 am

It goes without saying that it will need line-boring and honing after whatever caps are installed.

But the main question is obviously nobody knows WHAT the original cast caps were? Same as OEM LS6's or a better versions? Different casting material or what.

It's looking like either PRW or Neil and Parks Billets.

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Re: BBc old bow tie block

Post by ALKYAL » Fri Mar 16, 2018 2:59 pm

Kenny @ Pro Gram told me many yrs ago that the OEM BOW-Tie caps have a width that was approx .007/.008 wider than OEM Stock Block Caps. The BIG deal with The CAST Bow-Tie caps is the Material. They were Gray Cast Iron, NOT Ductial Cast Iron. They G.M. figured that they would be Replaced with Steel Caps/1-5. Went thru this many times back in the 90s and early 2000s
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