post #1 of Old 04-21-2013, 09:40 PM Thread Starter
paulbone
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1977 FSJ Cherokee 
 
Join Date: Mar 2012
Location: las vegas
Posts: 22
Head swap

Hi Guys

I have a good pair of rebuilt 360 heads from an 83 Chief and was going to use them on my 76 Chief.

Question is, the valve springs on the 76 are slighty longer and tighter than the ones on the 83 head.

Should I swap the springs over, or keep the 83 heads intact as they are.

Background;
The 76 is low milage snow plough, (40,000) but the heads are very badly carboned up, three push rods are bent into an S shape and several manifold studs sheared off. The truck has been sat for many years til I got hold of it.

Appreciate any advice.


Any advice would be appreciated.

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post #2 of Old 04-22-2013, 12:34 AM
revelc
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1985 FSJ Wagoneer 
 
Join Date: Nov 2011
Location: Tyler
Posts: 662
You should mic the cams and see if one is an aftermarket one thus requiring different springs.

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post #3 of Old 04-22-2013, 02:34 AM
pleontks
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1976 J-Series Truck 
 
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Location: Whetstone, Az
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check the holes for the bolts for your accessories. jeep changed the size around 80

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post #4 of Old 04-22-2013, 09:23 PM Thread Starter
paulbone
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1977 FSJ Cherokee 
 
Join Date: Mar 2012
Location: las vegas
Posts: 22
Thanks for your input.
The accessory holes all match up thankfuly.

I have since discovered that the spring lengths were changed in the 80's, anyone know why? The cam size didn't seem to change though?

I think I will put a new cam in anyway now after seeing that the lifters have a flat base.
Now to decide what cam to go for, hhhmmmmm?
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post #5 of Old 04-22-2013, 09:40 PM
super98lsc
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1999 WJ 
 
Join Date: May 2006
Location: Austin
Posts: 1,415
Honestly, you need to check the seat pressures and ensure they match the cam specs. example, you run too light of spring and it will float the valves before peak power and run like crap. If they are too tight you will wipe the lobes right of the cam in 500 miles. Of course coil bind is important too. Higher lift binds coils then you break springs and drop valves kaboom.

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post #6 of Old 04-23-2013, 02:54 AM
RockRollin
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1990 FSJ Wagoneer 
 
Join Date: Apr 2012
Location: Grand Haven Mi
Posts: 1,325
Replace springs with correct springs for cam everytime. Not much more $, cheaper than pullin it apart again, and no wondering

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Clawed: 90GW, TFI, Streetfire, 3"lift all spring, 31"BFG ATs, working RKE, Edel2131, Holly 1850, mild cam,
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post #7 of Old 04-23-2013, 08:35 PM Thread Starter
paulbone
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1977 FSJ Cherokee 
 
Join Date: Mar 2012
Location: las vegas
Posts: 22
Thanks for the advice gents.

I pulled the cam today and its right on the limit for wear.
Tonight I'm going to order a new cam with matching springs, timing gear etc.
That way i'll have peace of mind.

I'm after total dependability over perfromance, as I aim to treck down to South America in it when she's done.
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