[lust4speed]

It just seems that ARP is concerned with their bolt torque specs regardless of circumstances. I realize that it's risky to stick my neck out against a large company, but I still think I have a reason to doubt their published specs.

The difference between the stock crank bolt torque and the ARP is only 20 foot pounds, and that shouldn't hurt anything. The other thing about the balancer bolt is that tightening it to a higher torque value doesn't change any critical measurements.

Sticking with the manifold and the bolts securing it, Pontiac recommends 40 foot pounds and a dry installation - and this would be securing a cast iron manifold to a cast iron head. ARP gives three different torque values depending on which of their bolts are used - 45, 50, and 55 foot pounds using their Ultra Assembly Lubricant. So here's a 55 foot pound recommendation that might be securing an aluminum manifold to an aluminum head. The lubricant in place of the dry installation is also going to increase the tension on the threads. The compression holding the bolt from loosening in the case of aluminum to aluminum really isn't bolt stretch as much as compression of the manifold surface itself. I really don't want to find out just when the threads on the aluminum head start to pull.

[bulletpruf]

Originally Posted by lust4speed

It just seems that ARP is concerned with their bolt torque specs regardless of circumstances. I realize that it's risky to stick my neck out against a large company, but I still think I have a reason to doubt their published specs.

The difference between the stock crank bolt torque and the ARP is only 20 foot pounds, and that shouldn't hurt anything. The other thing about the balancer bolt is that tightening it to a higher torque value doesn't change any critical measurements.

Sticking with the manifold and the bolts securing it, Pontiac recommends 40 foot pounds and a dry installation - and this would be securing a cast iron manifold to a cast iron head. ARP gives three different torque values depending on which of their bolts are used - 45, 50, and 55 foot pounds using their Ultra Assembly Lubricant. So here's a 55 foot pound recommendation that might be securing an aluminum manifold to an aluminum head. The lubricant in place of the dry installation is also going to increase the tension on the threads. The compression holding the bolt from loosening in the case of aluminum to aluminum really isn't bolt stretch as much as compression of the manifold surface itself. I really don't want to find out just when the threads on the aluminum head start to pull.

I can tell you that ARP isn't concerned with the intake manifold integrity at 45, 50, or 55 ft/lbs. At 25 lbs, which is what Edelbrock recommends, the intake bolts and washers are already starting to dig into the manifold.

Scott

[bulletpruf]

Just finished building a TH400 for the engine and have been getting the car ready. Time to nail down the final details.

I scored some old headers from a PY member a few months ago. Don't know the brand, but they are full length, 1 5/8" primaries, 3" collectors. Blasted them this weekend and then hit them with some VHT high temp paint. I already have these and would like to use them, but am I going to be losing a lot of hp with these headers? Figure the engine would prefer 1 3/4" primaries, but I'm not too savvy on picking headers.

Rest of the exhaust won't be too exotic - either 2.5" or 3" with an X pipe and some quieter mufflers.

Thanks

Scott

[Region Warrior]

I'm still not sold on assembly lube vs 30w oil.
Just seems to thick. Maybe ARP rec's it do to thinner threads?

BTY BP.
Must of sold rkr studs yrs ago?... Only thing found is a set of rkr arms w/push rods.

[bulletpruf]

Ok, let me try this again - I scored some old headers from a PY member a few months ago. Don't know the brand, but they are full length, 1 5/8" primaries, 3" collectors. Blasted them this weekend and then hit them with some VHT high temp paint. I already have these and would like to use them, but am I going to be losing a lot of hp with these headers? Figure the engine would prefer 1 3/4" primaries, but I'm not too savvy on picking headers.

Any thoughts?

Thanks!

Scott

[Ron Landis]

NOTHING but Doug's would go on any Pontiac of mine. Get the coated...not simply for aesthetics...heat retention actually ads velocity to the exhaust gasses. JMHO. Your car deserves them! Take care. Ron

PS...any other brand should come with a "hedder-hammer"...Doug's Headers are very close...but touch nothing!

[bulletpruf]

Originally Posted by Ron Landis

NOTHING but Doug's would go on any Pontiac of mine. Get the coated...not simply for aesthetics...heat retention actually ads velocity to the exhaust gasses. JMHO. Your car deserves them! Take care. Ron

PS...any other brand should come with a "hedder-hammer"...Doug's Headers are very close...but touch nothing!

Ron - appreciate the input, but I'm on a budget on this car b/c I'm spending all my $ on my 70 GTO and 66 Fairlane. Already have these headers, so I really want to use them. Just trying to figure out if 1 5/8" primaries is going to choke this engine - pump gas 455, 9.3:1, Comp 274H, Performer RPM, one of Cliff's Q jets, ported 5C heads.

Scott

[Astock]

I really like 5/8's for the street, and it will be plenty for your app.

[72blackbird]

1 5/8" primary tube headers w/ 3" collectors will work, but you will feel the difference with 1 3/4" primary tube headers, especially in the midrange where having more exhaust volume will help. 455's and 461 strokers put out more exhaust than a 400 so you will definitely put the larger diameter primary tube to good use.

[gtofreek]

Originally Posted by lust4speed

It just seems that ARP is concerned with their bolt torque specs regardless of circumstances. I realize that it's risky to stick my neck out against a large company, but I still think I have a reason to doubt their published specs.

The difference between the stock crank bolt torque and the ARP is only 20 foot pounds, and that shouldn't hurt anything. The other thing about the balancer bolt is that tightening it to a higher torque value doesn't change any critical measurements.

Sticking with the manifold and the bolts securing it, Pontiac recommends 40 foot pounds and a dry installation - and this would be securing a cast iron manifold to a cast iron head. ARP gives three different torque values depending on which of their bolts are used - 45, 50, and 55 foot pounds using their Ultra Assembly Lubricant. So here's a 55 foot pound recommendation that might be securing an aluminum manifold to an aluminum head. The lubricant in place of the dry installation is also going to increase the tension on the threads. The compression holding the bolt from loosening in the case of aluminum to aluminum really isn't bolt stretch as much as compression of the manifold surface itself. I really don't want to find out just when the threads on the aluminum head start to pull.

I'll tell you a story about this. We do a fair amount of late model Hemi engines for twin turbo's and superchargers. We stud the mains with billet caps and use ARP studs. We get one set of studs and they say in their instructions to torque to 35 Ft. Lbs. and turn additional 90° and then another 90°. Keep in mind this is a 12 mm stud. that's a little smaller than out 1/2 Pontiac studs or BB Chevy studs. We could barely turn the first 90°. No way was it going another 90°. Keep in mind also that Jeff and myself are not small guys. We're both 6'1" and 225 lbs. We call ARP and ask what gives? They claim noone has ever called to complain or question this[we get that a lot, according to manufacturers we call about issues, they always say, "your the first to question it"]. They say that in their lab, under testing, that is what it takes to achieve the desired clamping force. Then he tells us if we use our angle gauge and torque to 35 Ft. Lbs. + 90, + 90, it will come out to around 110 Ft. Lbs. We tried it with our wrench set at 110 Ft. Lbs. and it clicked off after only 40°. We told them there is no way we are turning these things 180°. We are not buying this guy a new block after we pull the threads out. We asked if they ever tried tightening these studs like they say in an actual Hemi block. They replied, no. They test them in a 2" thick plate of tool steel, not a cast iron block. We told them we are not using their instructions and just torquing to 110 Ft. Lbs.

Now, all the instructions that now come with their Hemi stud kit say to toque to 105 Ft. Lbs. Imagine that!

[bulletpruf]

It lives! Cam is broken in. She's running good with plenty of oil pressure.

[adams81267]

Awesome! Can not wait to see and hear it.

[bulletpruf]

Originally Posted by bulletpruf

Just finished building a TH400 for the engine and have been getting the car ready. Time to nail down the final details.

I scored some old headers from a PY member a few months ago. Don't know the brand, but they are full length, 1 5/8" primaries, 3" collectors. Blasted them this weekend and then hit them with some VHT high temp paint. I already have these and would like to use them, but am I going to be losing a lot of hp with these headers? Figure the engine would prefer 1 3/4" primaries, but I'm not too savvy on picking headers.

Rest of the exhaust won't be too exotic - either 2.5" or 3" with an X pipe and some quieter mufflers.

Thanks

Scott

Any thoughts on the remainder of the exhaust system? Mandrel bent 2.5" with an X pipe or should I really step up to 3"? Thoughts on quiet mufflers? I don't want a drone and would be willing to sacrifice a few hp to keep the noise down.

Thanks,

Scott

[b-man]

A 2.5" exhaust is quieter than a 3" system.

I like the Dynomax Super Turbo 17749 20" case, quiet and powerful.

[bulletpruf]

Originally Posted by b-man

A 2.5" exhaust is quieter than a 3" system.

I like the Dynomax Super Turbo 17749 20" case, quiet and powerful.

Thanks, b-man.

Scott

[i82much]

I thought a 3 inch head pipe and 2.5 inch tailpipe was the best of both worlds.

[lust4speed]

I've got one street car with 3" mufflers and then reduced to 2-1/2", and another reduced down to 2-1/2" just before the mufflers - both extend to the bumper. I can't really tell any difference in power between the two systems. Both of them used a 6" long reducing cones to ease the transition, and I think the cones do help.

[bulletpruf]

Finally going to get to drive the car in a few weeks. Have been stationed overseas since 2013, but car is done and I'm flying back on Friday to take some leave. Now we'll see if the engine and transmission that I built will hold together!

Woohoo!

Scott