Im either retarded or I cant seem to find an ARP head bolt set for my 1997 carb HP500. I have two sizes.... 4.0625" and 2.0625". These are not 100% accurate as I measured with a tape measure real quick (caliper batteries too cold to work..smh) but they are pretty damn close. I called ARP and the 135-3601 kit has 3 different sizes with the long ones being different albeit not far apart. One size was shorter and one longer. Forget exact measurements as I wasnt able to write em down at that moment. These are for stock heads on stock block. I understand ARP may be longer for the washers but wouldnt it be ALL of them and being equal? What am I missing?

I had the box in my garage cabinet from the last engine top end I did. I used the 135-3601

496BB,

I just went down this road with my rebuilt 496. If you dig into their catalog, they sell bolts in 5packs, and they just assemble their kits from this inventory. You might just peruse their catalog, find bolts that work for your application and order them.

Pro tip.... Dial calipers are more reliable, less expensive and work at any temperature. Just sayin'....

Thanks. Brad.

Not to be a smartass, but if it is too cold for the calipers to work, probably too cold for engine assembly. Unless of course, you are just utzing around in an ice-cold shop to stay busy!

In two different shops. Cold was at home where I was. Engine at the heated shop.

Best bet is to measure and measure again. I went through a nightmare with my 525. I do see you’re working with a different motor but results may be similar.

The long bolts were too long, had a gap when torqued. I was recommended to bottom tap each hole as it will gain you a thread or so.

Did that, were still too long. Ultimately ended up machining the bolts down slightly putting a bevel on the end to avoid any cross threading.

All parts were bought through my builder who does tons of 525’s every year. Chalked it up to inconsistency in block manufacturing.

Hope this helps.

496,

Yup. Never one to shy away from modifying parts to fit the need, I wouldn’t hesitate at all to shorten bolts. Just make sure you have enough thread length, and the threads don’t shank out before you’ve taken up the grip length. You can’t just run a die up onto them to gain those threads back. Or, at least, I wouldn’t. Cut threads won’t be near as strong as rolled threads. It would be a shame to reduce ARP bolts to Lowe’s bolts by cutting an extra thread or two up the shank. Washers are a far better option.

Thanks. Brad.

To wrap this up I ordered the ARP 3601 and put those in. They are 3 different sizes instead of 2 but I put the two "medium" size ones inside valvetrain area on each end. Just weird they are not same as what was taken out but Im sure ARP is waaaay smarter than me. Size difference on the (4) medium bolts was only maybe 1/8" IF that. Not much at all. Thanks again for helping. I appreciate it. Never messed with the Gen6 motors. Ive built a few street Gen 7s though and mostly LS stuff so Im learning.

Yup, sounds similar. Stock vs ARP.