ARP vs Repo head bolts

[Mark P.]

[Joe L.]

Re: ARP vs Repo head bolts

I am rebuilding my 300HP 327 and am wondering if anyone used ARP head bolts and if they went through judging if they took a deduction.

I scanned the new 65 tech manual and judging guide and didn’t see this called out.

Do CC and Paragon have good reproductions ? Any other source ?

Any recommendations on which way to go ?

Thanks,

Mark

Mark------

I'm always concerned about reproduction fasteners used for critical-strength applications. After all, whoever manufactures them places on them the ID marking of defunct fastener manufacturers. In doing so, what does not appear is the actual manufacturer's ID marking. That gives them "cover". As I've said before, I consider such fasteners to be, essentially, forgeries. A manufactuer's ID marking is like a signature and should be as inviolate as a signature.

For me, if I were lacking NOS bolts, I'd go with the ARP bolts. If original configuration were not a concern, I'd go with the ARP bolts over NOS bolts. I like ARP fasteners which are among the best you can buy short of aerospace.

One thing you could do is to use the ARP bolts for the under valve cover positions and use reproductions for those short bolts on the lower row which are visible.

What about used, original bolts? Well, if the bolts are "first run" (i.e. removed from an engine that was last assembled at the factory) and not damaged in any way, I say it's OK to re-use them. If they are of "uncertain history" or damaged in any way, I would not use them.

[Mark P.]

Re: ARP vs Repo head bolts

Joe - thanks for that advice. I am not planning anything more than Chapter flight judging so I have made minor upgrades to make this car a nice driver. I want a car where I am not afraid of a rock chip while driving. My rebuilder prefers ARP head bolts but wants to use my OEM main bolts.


I just checked my judging sheets and it looks like the head bolts are not judged. In that case I will probably stay with the ARP bolts I bought.

Thanks Mark

[Gene M.]

Re: ARP vs Repo head bolts

...............

I just checked my judging sheets and it looks like the head bolts are not judged. In that case I will probably stay with the ARP bolts I bought.

Thanks Mark

That is NOT a true statement. Everything on the car is SUPPOSED to be judged, listed or not on judging manual.

[Leif A.]

Re: ARP vs Repo head bolts

That is NOT a true statement. Everything on the car is SUPPOSED to be judged, listed or not on judging manual.

I completely agree with Gene on his statement.

[Mark P.]

Re: ARP vs Repo head bolts

If anyone has ever lost a point for incorrect head bolts then I hope they speak up. I reviewed the 4 pages of the Mechanical section of the judging sheets for 63-67 and I don't see where it would be deducted. Item 2 for Cylinder Case and Item 3 for Cylinder Heads don't seem to allow for a head bolt deduction.

I called Paragon and they say their head bolts are US made and grade 8 and correctly rated at 15,900 lbs tensile strength which matches the tables I have looked at for a 7/16-14 bolt. They have the TR head mark which they say is correct for my 65 and better than the double circle option they recommend for earlier cars.

[Gene M.]

Re: ARP vs Repo head bolts

If anyone has ever lost a point for incorrect head bolts then I hope they speak up. I reviewed the 4 pages of the Mechanical section of the judging sheets for 63-67 and I don't see where it would be deducted. Item 2 for Cylinder Case and Item 3 for Cylinder Heads don't seem to allow for a head bolt deduction. ..................

I see from your profile you do not have much experience in the NCRS judging system. To make a decision of what is judged and not is like “out of your pay grade” .

[Mark P.]

Re: ARP vs Repo head bolts

Gene - I haven't judged very much which is why I am trying to sort this issue out. I said it 'looks like it isn't judged" based on the judging sheets on my car and a review of the 6th edition of the judging guide. How many points do you think an experienced judge would take off for this ? I have to decide if the point hit is worth going with reproduction bolts. Would you go with used original bolts that you don't know the history on, buy GM NOS bolts that have incorrect head markings, use a reproduction bolt or just use an ARP bolt ? My rebuilder wants me to use ARP bolts.

I don't want to spread any incorrect info but I don't see an option to edit an erroneous post.

Thanks,

Mark

[Keith B.]

Re: ARP vs Repo head bolts

of the millions of 283, 307,327, and 350's out there I would source good used bolts and move on

[Gene M.]

Re: ARP vs Repo head bolts

Gene - I haven't judged very much which is why I am trying to sort this issue out. I said it 'looks like it isn't judged" based on the judging sheets on my car and a review of the 6th edition of the judging guide. How many points do you think an experienced judge would take off for this ? I have to decide if the point hit is worth going with reproduction bolts. Would you go with used original bolts that you don't know the history on, buy GM NOS bolts that have incorrect head markings, use a reproduction bolt or just use an ARP bolt ? My rebuilder wants me to use ARP bolts.

I don't want to spread any incorrect info but I don't see an option to edit an erroneous post.

Thanks,

Mark

There are no “not judged parts on a Corvette” if you can see it it is evualated......period.

My guess the short lower head bolts (only ones ya can see) would be valued at about 3 points. Some judges my see it as more some others less but it will be in that range 2 to 4.

Joe gave you some good advice GM short bolts you can see and ARP for the rest.

[Mark P.]

Re: ARP vs Repo head bolts

Thank you Gene. This helps me a lot.