PRH
Well-Known Member
So, the lobe that you measured in place at .297, checks .323 with the caliper?
Cam swap without pulling motor
- Thread starter Earlie A
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If the AC hoses both enter from the same side you can move it off to the side.
You can cut some wood to span the inner fender wells and rest compressor on the wood and take the engine apart.
Remove hood and hang the compressor from above so it's out of the way.
Lift compressor with cherry picker and work around it.
PRH
Well-Known Member
If you get a chance when you’re messing with the heads……..check what the difference in installed height is between the exhaust with the rotator, and the intake with the retainer.
I haven’t had a set of heads here with rotators on them in so long, I’ve forgotten how much difference there is.
The heads with rotators on them that I’ve worked on had exhaust valves with 2 grooves instead of the typical 4.
I haven’t had a set of heads here with rotators on them in so long, I’ve forgotten how much difference there is.
The heads with rotators on them that I’ve worked on had exhaust valves with 2 grooves instead of the typical 4.
PRH
Well-Known Member
Yeh, not a great choice for low CR and exhaust manifolds.
I was told by the seller that the motor in the truck had only a few hundred miles on a fresh rebuild. I was skeptical, but I have not found anything to dispute the claim. Pistons are 0.030 over. There is no ridge at the top of the bores other than a few places I can feel the slightest amount of carbon. Zero sludge anywhere.
Look at the pictures of the CC. What can you guys tell me about the tuning job?
Look at the pictures of the CC. What can you guys tell me about the tuning job?
PRH
Well-Known Member
One sign that’s always a red flag for me is…….when the head/deck surfaces have been subjected to some “cookie dusting”
It wouldn’t surprise me if the extent of the cylinder head “rebuilding” consisted of much more than cleaning, valve lapping, new seals.
But that will be revealed after they’re torn down.
Did you locate a casting number under the runners?
As for the tune up……”meh”
Pretty typical of low CR, big cam(low cyl pressure), unleaded fuel.
It wouldn’t surprise me if the extent of the cylinder head “rebuilding” consisted of much more than cleaning, valve lapping, new seals.
But that will be revealed after they’re torn down.
Did you locate a casting number under the runners?
As for the tune up……”meh”
Pretty typical of low CR, big cam(low cyl pressure), unleaded fuel.
Professor Fate
Push the button, Max...
I'm really hoping that pic of #4 piston is just a trick of the camera...
Yeah. It’s the flash.
PRH
Well-Known Member
I’m confident that heads that used rotators on the exhaust valves did not get springs with dampers(for either valve).
I’m also pretty sure the rotators wouldn’t be paired with 4 groove valves.
(The reason for the 4 grooves is to provide rotation)
My recollection is that the installed height for a 4 groove ex valve ends up slightly taller than the 2 groove ex valve(when checked on the same head with the same retainer).
I’ll look thru my stash to see if I have a two groove ex valve kicking around.
If I do, I’ll do the measurement….just for some added “content”.
Edit- I don’t have a 2 groove ex valve on hand.
Can you check the coil bind height of that exhaust spring?
I’m curious to see how far from coil bind it was in operation.
I’m also pretty sure the rotators wouldn’t be paired with 4 groove valves.
(The reason for the 4 grooves is to provide rotation)
My recollection is that the installed height for a 4 groove ex valve ends up slightly taller than the 2 groove ex valve(when checked on the same head with the same retainer).
I’ll look thru my stash to see if I have a two groove ex valve kicking around.
If I do, I’ll do the measurement….just for some added “content”.
Edit- I don’t have a 2 groove ex valve on hand.
Can you check the coil bind height of that exhaust spring?
I’m curious to see how far from coil bind it was in operation.
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PRH
Well-Known Member
Interesting that the casting number is missing a digit.
Should be 3418915.
From that pic, it appears the heads were actually resurfaced.
Should be 3418915.
From that pic, it appears the heads were actually resurfaced.
PRH
Well-Known Member
Thanks for checking the spring.
Okay, so it’s not a 340 replacement spring……those coil bind at basically 1.100”.
Were there any shims under the intake springs to get the installed height more equal between in/ex?
Okay, so it’s not a 340 replacement spring……those coil bind at basically 1.100”.
Were there any shims under the intake springs to get the installed height more equal between in/ex?
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PRH
Well-Known Member
What are you leaning towards for a cam?
Not a lot for SBM cams in stock at some of the bigger outlets.
Not a lot for SBM cams in stock at some of the bigger outlets.
PRH
Well-Known Member
Sounds about right.
I revamped a 360 years ago that had been built by a local builder.
“9:1, 400hp”
It would hardly turn a tire.
He ran it for a couple years then wanted it hopped up a bit.
Pulled it apart, measured everything…….7.7:1.
junkyardhero
Well-Known Member
no me gusta. even with stall and gears that's a terrible cam for a truck and even more so with a wheeze bag 8:1 smogger 360
i know that i'll get absolutely dragged for this, but i'd go small. MP used to make the P4452757 which is .410/.425 248/256 110* which yes, i know is smaller than a stock 360 4bbl cam, but is absolutely the cats *** in this kind of motor.
without addressing the compression issue, i'd firmly be in the camp of sub .450 lift, under 260 duration, and less than 114 (110~112 ideal).
Anyone know of a 0.030 piston that will get to zero deck or slightly out of the hole? If I measure the bores and they check out good is it safe to hone and go 0.030 over again or do I need to assume 0.040 over if I change pistons?
Looks like all the pistons I find are made to order.
Looks like all the pistons I find are made to order.
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