Head Bolt Question.

[krazedstang]

I'm starting to get my engine put together, and the ARP head bolts that I had purchased from someone seem to be the 1/2 instead of 7/16. so I was on ARP and can't decide what the difference is between
The Official ARP Web Site | Kits and these The Official ARP Web Site | Kits Except the $100 difference?

 

[84Ttop]

Brand:ARP

Manufacturer's Part Number:154-3605

Part Type:Cylinder Head Fasteners

Product Line:ARP High Performance Series Cylinder Head Bolt Kits

Summit Racing Part Number:ARP-154-3605

UPC:672036019402

Fastener Style:Bolt

Undercut Stud:No

Head Style:Hex

Fastener Material:Chromoly

Fastener Finish:Black oxide

Washers Included:Yes

Cut to Fit:No

Quantity:Sold as a kit.

Notes:Includes 1/2 in. to 7/16 in. insert washers for cylinder heads with 1/2 in. bolt holes.




Brand:ARP

Manufacturer's Part Number:154-3601

Part Type:Cylinder Head Fasteners

Product Line:ARP High Performance Series Cylinder Head Bolt Kits

Summit Racing Part Number:ARP-154-3601

UPC:672036003692

Fastener Style:Bolt

Undercut Stud:No

Head Style:Hex

Fastener Material:Chromoly

Fastener Finish:Black oxide

Washers Included:Yes

Cut to Fit:No

Quantity:Sold as a kit.



The only difference I see is the step washers. What heads do you have? this will determine if you will need them or not

 

[krazedstang]

@84Ttop I have the Trick Flow 170's

 

[squeak93]

1/2 bolts are for a 351 or 302 that has been machined for them. If your 302 is stock you will likely need the 7/16 AND the 1/2 inserts as your heads are machined for 1/2 holes but the block will only take a 7/16

 

[84Ttop]

@84Ttop I have the Trick Flow 170's

You do not need the step washers, The TFS 170's have 7/16 tapered holes out of the box. The top of the whole is 7/16" and the bottom is 1/2", This allows you to use a standard head bolt without trouble. It also makes it easy to open the wholes up later to 1/2" if you ever use them on a 351 or aftermarket block

 

[84Ttop]

1/2 bolts are for a 351 or 302 that has been machined for them. If your 302 is stock you will likely need the 7/16 AND the 1/2 inserts as your heads are machined for 1/2 holes but the block will only take a 7/16

This is incorrect, please see my post above

 

[squeak93]

I apologize, I assumed he was looking at step bolts due to his heads were already opened up to 1/2 bolt holes.

84 is correct, if they are out of the box stock, then you just bolt them down with 7/16 bolts.

 

[krazedstang]

You do not need the step washers, The TFS 170's have 7/16 tapered holes out of the box. The top of the whole is 7/16" and the bottom is 1/2", This allows you to use a standard head bolt without trouble. It also makes it easy to open the wholes up later to 1/2" if you ever use them on a 351 or aftermarket block

Awesome, then it'll get the ones without the step washers.