older iron heads
Thread Starter
|
Senior User
Joined: Feb 2004
Posts: 185
Likes: 0
From: Crownsville, MD
older iron heads
OK, now I got the bug. This forum is great but it is gonna empty my bank account if I don't watch out. At first I thought I might want to do a minor build up (ala Performer package) but now you guys have me thinking I should take it a bit further.
Besides money (and knowledge), I think my biggest limitation is my compression ratio. I think my 1976 390 came with 8.6:1 compression. The engine is stock except for the Edelbrock SP2P manifold, Holley 4V and Thorley headers.
I am now thinking maybe going Performer RPM intake, 700 cfm carb, Crane 941 cam, Edel roller chain and maybe a DUI down the road. My concern is the compression will be too low to get the full benefit of this cam (at least according to Crane). On another thread StephenW mentioned using high-intensity lifters to compensate for low CR. Are there other options, other than tearing down the bottom half of the engine and putting in new pistons, to increase CR? Would switching to a different set of heads help? I see that there are a lot of the old C#### heads for sale on the net. Can I pick up some compression and performance by switching to some older iron heads? I see DSC has used C6AE-R, C1AE, C4AE, and C8AE-H heads available in the $200 range.
Besides money (and knowledge), I think my biggest limitation is my compression ratio. I think my 1976 390 came with 8.6:1 compression. The engine is stock except for the Edelbrock SP2P manifold, Holley 4V and Thorley headers.
I am now thinking maybe going Performer RPM intake, 700 cfm carb, Crane 941 cam, Edel roller chain and maybe a DUI down the road. My concern is the compression will be too low to get the full benefit of this cam (at least according to Crane). On another thread StephenW mentioned using high-intensity lifters to compensate for low CR. Are there other options, other than tearing down the bottom half of the engine and putting in new pistons, to increase CR? Would switching to a different set of heads help? I see that there are a lot of the old C#### heads for sale on the net. Can I pick up some compression and performance by switching to some older iron heads? I see DSC has used C6AE-R, C1AE, C4AE, and C8AE-H heads available in the $200 range.
Elder User
Joined: Nov 2003
Posts: 936
Likes: 0
You probably already have the C8AE-H heads on your engine. You may have some D2's (I can't remember the full casting number for that head) but these have the same combustion chamber size as the C8's and as far as I know are really the same head just that it was produced in the 70's with the D2 casting number. I could be wrong though. You may just pull the heads, have some porting and polishing done or do that yourself (be better to send it to someone who really knows though and has a flow bench) and switch to steel shim type head gaskets (I believe you have the thicker composite type) and that should get you a little over 9.1:1 comp ratio.
Thread Starter
|
Senior User
Joined: Feb 2004
Posts: 185
Likes: 0
From: Crownsville, MD
Correction. I said my compression is 8.6:1 but after searching a bit further, I am now thinking the stock compression in my 1976 390 is 8:1.
Based on what Annihilator said, it sounds like there would be no point in getting any of the older model iron heads and they wouldn't help with compression either. But it does sound like a combination of some milling my existing heads and a steel gasket would move me up closer to 9:1 (I hope) which is in the recommended range for the Crane 941 (8.75:1 to 10.75:1). Will a decent machinest be able to estimate that amount of milling needed or is this just trial and error? I guess I could have some mild port work done while the heads are at the machine shop also (I just can't stop coming up with ways to spend more money).
Thanks for the help guys.
Based on what Annihilator said, it sounds like there would be no point in getting any of the older model iron heads and they wouldn't help with compression either. But it does sound like a combination of some milling my existing heads and a steel gasket would move me up closer to 9:1 (I hope) which is in the recommended range for the Crane 941 (8.75:1 to 10.75:1). Will a decent machinest be able to estimate that amount of milling needed or is this just trial and error? I guess I could have some mild port work done while the heads are at the machine shop also (I just can't stop coming up with ways to spend more money).
Thanks for the help guys.
Posting Guru
Joined: Nov 2003
Posts: 1,888
Likes: 1
From: Iowa
i think your mechanist should be able to tell you how far to go on the milling, but i know if you go much more than .030 milling the heads you should have the intake milled .030 to match the heads sitting down farther, but i think if you get the heads milled oh say .020, you can justify the ports when you port the heads, if you do port your heads concentrate on the exhaust a little bit more because with all that air comeing in you need a good free flowing exhaust to get rid if it.
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Instead of milling the intake mill the intake side of the head. This way any intake will bolt to it and work correctly. If you mill the bottom of the head and the intake you end up with two oddball pieces that will only work together.
I would not mill the heads to get your compression up from 8.1. You will not gain much this way. New pistons would be the only way to go. Plus you can get your quench set properly to reduce the chances of detonation.
I would not mill the heads to get your compression up from 8.1. You will not gain much this way. New pistons would be the only way to go. Plus you can get your quench set properly to reduce the chances of detonation.
Cargo Master
Joined: Aug 2000
Posts: 2,931
Likes: 12
From: SW Michigan
iron heads
There are just 2 possibilities here, head wise. Most of the iron heads had BIGGER chambers than the C8AE-H or D2TE-AA heads your engine is probably wearing now. There were a couple of 'high performance' 352 or 390 heads made that had smaller chambers.....I think in '60 and '61, but the exact part number esacpes my memory right now. You could look for some of those....Dennis should have them.....or you could mill the heads .060 and run steel shim gaskets- but you still have too much quench clearance, like RS said, and new pistons would be a better fix, like RS said, and you should NEVER mill and intake manifold, like RS just told you...that guy is getting pretty sharp, good job Sean ! Do you need some piston numbers ? DF
Trending Topics
Junior User
Joined: May 2003
Posts: 97
Likes: 0
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
Post Fiend
Joined: Jan 2003
Posts: 8,600
Likes: 4
From: Iowa
Ok here's your shopping list for things you probably wont find. 
I'll post heads / cc's:
COAE-6090-C / 59.7 - 62.1
C2SE-6090-B / 62.6 - 64.6
C3AE-6090-C / 56.4 - 61.0
DSC might have 'em, give 'em a call.
I agree though, flat top pistons with the correct compression height would be the best solution.
I'll post heads / cc's:
COAE-6090-C / 59.7 - 62.1
C2SE-6090-B / 62.6 - 64.6
C3AE-6090-C / 56.4 - 61.0
DSC might have 'em, give 'em a call.
I agree though, flat top pistons with the correct compression height would be the best solution.
Thread
Thread Starter
Forum
Replies
Last Post
Rusty_S
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
3
Jul 22, 2015 01:40 PM
7Ford6
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
9
May 20, 2010 10:04 AM
moonley
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
2
Mar 19, 2007 09:07 AM
Jsbiohazard
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
15
Mar 13, 2006 01:33 PM
karlsd
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
11
Nov 7, 2001 11:31 PM
