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ARP HEAD BOLTS

WS6 said:
Being frugal I put a set together from Summit individually. I called ARP and was told what the previous poster was told and that 2 3/8 and 3 1/2 were not made by them. They gave me the same part numbers as above and I odered them for $74 shipped. Now the short ones are being dropped shipped from ARP and they come with the chamferred washers included.

HAP 4500-5 (4)
HAP 3450-5 (4)
HAP 2400-5 (8)
washer number is 200-8509,but are included from Summit.


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Thanks, Made it easy ordering the arp bolts, got them from summit.
 
GNTTA said:
These are all 7/16 bolts with 14 threads per inch.
4 bolts 4 1/2 inches long
4 bolts 3 1/2 inches long
8 bolts 2 3/8 inches long

Torque to 25fp then 50 then 80. Wait a full day back off and re-torque to 80fp.
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Where did these bolt lengths come from? Are these the lengths of the stock bolts?
 
Probably Jan, those were in a pdf of the bolt sizes and well as 16 washers are needed. I got my Arp bolts and washers from Summit, and WS6 got his there also. The summit arp. part #s are listed in this thread. I would not be wise to use stock head bolts, Arp bolts are much stronger!
 
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Does anyone have a old set of stock bolts they took out and saved, or don't want anymore? If someone does, could they measure the lengths or send them to me?
 
BuickGN said:
Does anyone have a old set of stock bolts they took out and saved, or don't want anymore? If someone does, could they measure the lengths or send them to me?
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Sorry can't help here as I don't have a set of originals (an now that you reminded I'm keen on getting hold of a set lol).

Just want to say don't use old original bolts as they are torque to yield and have stretched once used; hence always use new ones or go the ARP route.

Also if I remember correct FelPro do have a bolt kit for the TTA but I might be wrong ...
 
Jan Larsson said:
Sorry can't help here as I don't have a set of originals (an now that you reminded I'm keen on getting hold of a set lol).

Just want to say don't use old original bolts as they are torque to yield and have stretched once used; hence always use new ones or go the ARP route.

Also if I remember correct FelPro do have a bolt kit for the TTA but I might be wrong ...
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In hindsight I wish I kept the old ones I just threw out. I just can't believe I didn't think of that. When I started this I didn't know the bolts for this are so specialized. I just wanted to know if the measurements at the beginning of this sticky are measured from stock bolts. If they are that I got a basis to work from. The problem I just had was my body couldn't get the headers in easy because the ARP head of the bolts is tall. The Fel-Pro seem to be stock height. But want to get a basis for bolt measurements.
 
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BuickGN said:
In hindsight I wish I kept the old ones I just threw out. I just can't believe I didn't think of that. When I started this I didn't know the bolts for this are so specialized. I just wanted to know if the measurements at the beginning of this sticky are measured from stock bolts. If they are that I got a basis to work from. The problem I just had was my body couldn't get the headers in easy because the ARP head of the bolts is tall. The Fel-Pro seem to be stock height. But want to get a basis for bolt measurements.
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I presume the ARP length are just the closest to the stock bolts they have that match up.

The OEM part numbers are as follows and the first two are standard ones used on the 3800 engines and the last part number is also commonly used. I remember Bill Owen told me they pulled out all the standard head bolts they used at the time to find a good set that would work without having to add another part number which would add cost and possibly make the project a no go.

25533811 (8 in total) and is 7/16-14X2.34" from what I find on-line
25527831 (4 in total)
25525953 (4 in total)

Should also point out that the original engine assembly manual from B-O-C don't show any washers being used so hence the ARP's being slightly longer possibly.

All above part numbers still show as available.
 
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Here are the part numbers I have used on a stock 109 block and TTA heads. These are for BOLTS from ARP

8 x HAP 2.400-5
4 x HAP 3.450-5
4 x HAP 4.500-5
16 x Washer 200-8509
 
Jan Larsson said:
I presume the ARP length are just the closest to the stock bolts they have that match up.
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That's why I'm going through all this. I don't want to assume. I appreciate all the responses also. I would like to get confirmation from the stock bolts just so I and everybody knows what the baseline is.
 
Might be isolated issue with headers if yours were the only problem. I would install those sizes based on the experiences of others here and not loose any sleep over it.
 
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FYI to those looking for the stronger PRO Series ARP 12-point head bolts, these are rated at 200 tensile strength over the Hi-Performance Series ARP 6-point head bolts rated at 180 tensile strength.

Here are the part numbers to buy direct from ARP:

7/16-14 x 2.375" (8)
ARP P/N 5AP-2.500-1 ($4.62 ea.)
(note these are .125" longer)

7/16-14 x 3.500" (4)
ARP P/N 5AP-3.450-1 ($4.96 ea.)
(note these are .050" shorter)

7/16-14 x 4.500" (4)
ARP P/N 5AP-4.500-1 ($5.45 ea.)

7/16 Washers (16)
ARP P/N 200-8509 ($0.99 ea.)

-Scott
 
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