86 F150 300 Build Questions
#31
10-25-2018, 08:59 PM
You are correct. 85 and 86 heads use bolt down rockers. I used the description of "pedestal mount rockers" which is the same as bolt down.
The advantage of the carb head is that there is better flow under .400" valve lift than the EFI head because the EFI combustion chamber is designed to shroud the valves in order to create swirl.
We recently did a flow bench comparison between the carb and EFI head to verify this.
The larger carb head combustion chamber will still allow you to get in the desired range for a compression ratio that will work with the Comp 260 cam using off the shelf hypereutectic pistons.
The advantage of the carb head is that there is better flow under .400" valve lift than the EFI head because the EFI combustion chamber is designed to shroud the valves in order to create swirl.
We recently did a flow bench comparison between the carb and EFI head to verify this.
The larger carb head combustion chamber will still allow you to get in the desired range for a compression ratio that will work with the Comp 260 cam using off the shelf hypereutectic pistons.
What pistons are you going to use?
pmuller,
I believe I am going to go with an 85/86 carbed head if you do not see any issue with it, the comp cam 268, and the Silv-O-Lite 1186H pistons.
I assume the compression ratios below were referring to the carbed head?
8.4 static compression ratio which again gives you a DCR around 7.
Thanks,
Cody
#32
10-26-2018, 10:03 AM
pmuller,
I believe I am going to go with an 85/86 carbed head if you do not see any issue with it, the comp cam 268, and the Silv-O-Lite 1186H pistons.
I assume the compression ratios below were referring to the carbed head?
8.4 static compression ratio which again gives you a DCR around 7.
Thanks,
Cody
You will need a degree wheel and a dial indicator with a magnetic base to get the job done.
#33
11-01-2018, 08:26 PM
#34
11-01-2018, 09:00 PM
A cam is considered to be installed neutral when the intake lobe center is the same distance from TDC as the exhaust lobe center.
So if a cam with a 110* LSA is installed with the intake lobe center at 110* ATDC the exhaust lobe center will be 110* BTDC
If the cam is advanced 4* the intake lobe center will be at 106* ATDC and the exhaust lobe center will be at 114* BTDC.
#35
11-02-2018, 07:34 PM
That is actually a good question.
A cam is considered to be installed neutral when the intake lobe center is the same distance from TDC as the exhaust lobe center.
So if a cam with a 110* LSA is installed with the intake lobe center at 110* ATDC the exhaust lobe center will be 110* BTDC
If the cam is advanced 4* the intake lobe center will be at 106* ATDC and the exhaust lobe center will be at 114* BTDC.
A cam is considered to be installed neutral when the intake lobe center is the same distance from TDC as the exhaust lobe center.
So if a cam with a 110* LSA is installed with the intake lobe center at 110* ATDC the exhaust lobe center will be 110* BTDC
If the cam is advanced 4* the intake lobe center will be at 106* ATDC and the exhaust lobe center will be at 114* BTDC.
I can not thank you enough for answering all of my questions. You are an absolute plethora of knowledge and I am learning more and more from you every time I log onto this forum.
Do you think the following will work for checking the cam degree.
Multi-Position Magnetic Base with Fine Adjustment
https://www.harborfreight.com/multi-...ent-63663.html
1 In. Travel Machinist's Dial Indicator
https://www.harborfreight.com/1-in-t...tor-63521.html
Competition Cams 4787 7.5" Sportsman Degree Wheel
#37
11-02-2018, 08:33 PM
The magnetic base and dial indicator will be fine.
Get at least a 9" degree wheel which will be easier to read than a smaller wheel.
https://www.amazon.com/Competition-C...70_&dpSrc=srch
Get at least a 9" degree wheel which will be easier to read than a smaller wheel.
https://www.amazon.com/Competition-C...70_&dpSrc=srch
#39
01-28-2019, 11:14 AM
Well, it has been a while sense I have been on the forum. I had to sit aside my rebuild after finding out we were expecting a baby boy in May of this year.
I couldn't be happier about the new change in our life, but I am still amped up on getting the engine and truck back together.
pmuller,
If you are still hanging around this section, I promise I will have another annoying amount of questions for you on the inline 6.
Thanks,
Cody
I couldn't be happier about the new change in our life, but I am still amped up on getting the engine and truck back together.
pmuller,
If you are still hanging around this section, I promise I will have another annoying amount of questions for you on the inline 6.
Thanks,
Cody
#41
03-30-2024, 08:17 PM
got a question on all this I am doing the same thing I have a 68 block border .40 over the head is a 95 efi with the 268 comp cam I have a 600 cfm holley street warrior carb and hei distributor with flam thrower coil do I have anything to worry about with keeping the head stock other then the spring that come with the cam and gears as well kinda on a budget with this seems to run really well at idel having gotten to take it up the road yet just wanna make sure I don't mess anything up
Last edited by Devindockery97; 03-30-2024 at 08:20 PM.
#42
03-31-2024, 07:31 AM
got a question on all this I am doing the same thing I have a 68 block border .40 over the head is a 95 efi with the 268 comp cam I have a 600 cfm holley street warrior carb and hei distributor with flam thrower coil do I have anything to worry about with keeping the head stock other then the spring that come with the cam and gears as well kinda on a budget with this seems to run really well at idel having gotten to take it up the road yet just wanna make sure I don't mess anything up
The HEI distributor has way too much mechanical advance along with an aggressive curve.
We have seen several engines with piston and ring damage because of it.
Here is a link to one of the latest damaged 4.9 engines with an HEI distributor.
https://www.fordsix.com/threads/92-f...28/post-702007
As far as the EFI head, we typically replace the exhaust valve spring retainers with intake retainers and use .050" up keepers to raise the retainer on the exhaust valve closer to the same height as the intake retainer.
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