Vintage Mustang Forums banner
Cancel
Create thread New Garage Forums

289 Head Build - What Cam to use?

Jump to Latest
1 - 20 of 64 Posts

Turnall

· Registered
Joined
·
9,019 Posts
Discussion starter · #1 ·
So took the heads that I bought for the 289 block that's at the machine shop and the first question asked was: What cam are you going to use? Uh well, uh, I'm not sure yet...

So, I have to make a decision on what cam to use now so my man knows how to "set up" the heads. I'm using a 1M crank and planning on using flat top hypereutectic pistons. I'm looking for close to the 10:1 compression ration touted by Ford back in '66 on the "A" code engine (this is what this GT is supposed to have in it). It will have the 4bbl intake and Autolite 4100 carburetor. I'm trying to get 275-300hp. Strictly street and a weekend driver.

If more information is needed, let me know...but I need to know my options for the cam and where to buy. :nerd:

Thanks,

Allen
 
#2 ·
What heads (casting number, date code) are you using?
What do you mean by head 'set up'?
Have you done the calculations to determine what your static compression ratio (CR) will be with 'flat top' pistons, compression height, head gasket, deck clearance, etc?
Auto or manual trans?
What CFM is the 4100?
Do you want low end torque or high end HP?
Why do you have specific HP number requirement for a 'strictly street and a weekend driver'?

Paul
 
Save
Reply Quote Like Like
Discussion starter · #3 ·
Paul1958 said:
What heads (casting number, date code) are you using? C60E - 5H31 and 5J2
What do you mean by head 'set up'? I think springs and valves.
Have you done the calculations to determine what your static compression ratio (CR) will be with 'flat top' pistons, compression height, head gasket, deck clearance, etc? No. Not sure how, plus the block is at one shop and the heads at another.
Auto or manual trans? Auto.
What CFM is the 4100? 480
Do you want low end torque or high end HP? It's not going to be a racer, so just wanting it close to stock.
Why do you have specific HP number requirement for a 'strictly street and a weekend driver'? The hp given from the factory was 221 for an "A" code and 271 for the "K" code engine. I want to make sure I can get this kind of horsepower while keeping the engine close to stock.

Paul
Click to expand...
Hope some of that makes sense...

Allen
 
#4 · (Edited)
31 Aug and 2 Sept 1965 - clearly 1966 production.

C60E-M? Does your exhaust port look like this (notice extra material at one threaded hole at each port):
Image


Image



Paul
 
Save
Reply Quote Like Like
#6 ·
Turnall said:
http://forums.vintage-mustang.com/vintage-mustang-forum/963641-289-heads-ported.html

This is a photo I posted on another thread a couple of weeks back...

Hope that helps, I don't have them to take pictures now...

Allen
Click to expand...
Yep - I remember that thread - modified C6OE-M. On pump gas I would not go over about 10:1 static so you will need to do some calculations to determine your static CR based on the chamber size, head gasket thickness, compression height/deck clearance, and piston crown configuration, etc. Those heads have 52.5-55.6 cc chambers which are fairly small. Are you having the engine overbored?

Paul
 
Save
Reply Quote Like Like
Discussion starter · #8 ·
Yes. Was an old (stock) block. Not sure yet if the shop is going .030 or .040 over, but will be one of the two. Machine shop is also turning the crank for me. The two shops have worked with each other before (smaller city and both been in business a while). I have also done business with both, but never from "scratch" like I'm doing this.

Ok, calculating the CR just sent my head spinning...:shrug:

I don't have anything to check the chamber size (I did watch a guy on youtube one time)...lol. I will be buying the head gasket. Do I just need to plan on getting a certain size or ask the shops what the clearance will be and what to use? The pistons will be flat top, if that helps any...

Allen
 
#10 ·
Turnall said:
Yes. Was an old (stock) block. Not sure yet if the shop is going .030 or .040 over, but will be one of the two. Machine shop is also turning the crank for me. The two shops have worked with each other before (smaller city and both been in business a while). I have also done business with both, but never from "scratch" like I'm doing this.

Ok, calculating the CR just sent my head spinning...:shrug:

I don't have anything to check the chamber size (I did watch a guy on youtube one time)...lol. I will be buying the head gasket. Do I just need to plan on getting a certain size or ask the shops what the clearance will be and what to use? The pistons will be flat top, if that helps any...

Allen
Click to expand...
No need to spin - use one of the online CR calculators. You need to know what the deck/compression height will be and what the overbore will be from your machine shop(s). I gave you the chamber size - thats why I asked exactly which heads you had. Do you know what head gasket you are using?

BTW I could also just tell you to use this/that cam from a catalog but that is the wrong way to select a cam that will work for your application or driving style. A lot of factors should be looked at when selecting the good cam - especially static CR, dynamic CR (there are online dynamic CR calculators), driving style (street) or power requirement (race), etc. Cam will determine you entire engine's 'personality', what RPM range for power, etc. Are you considering a roller cam?

Paul
 
Save
Reply Quote Like Like
Discussion starter · #11 ·
Using the calculator from Fastback97, I just plugged in some numbers (albeit off a flat top piston page) to see how the calculator works. So if I keep everything equal to what is showing except the deck height, I can of course change the ratio. Do the other numbers look correct with .030" over and flat top pistons and the fel-pro gasket Fastback suggested?

Allen
 

Attachments

#12 ·
Turnall said:
Using the calculator from Fastback97, I just plugged in some numbers (albeit off a flat top piston page) to see how the calculator works. So if I keep everything equal to what is showing except the deck height, I can of course change the ratio. Do the other numbers look correct with .030" over and flat top pistons and the fel-pro gasket Fastback suggested?

Allen
Click to expand...
even flat top pistons have -cc due to the reliefs for the valves.

bore = 4.030
stroke = 2.87
head CC= 53-55
gasket = .039
deck height = what the machine shop makes it. factory is roughly .016 in the hole (how far the piston sits down below the deck surface

typical flat tops are 2.7-5 cc's due to valve reliefs. Some calculators use -2.7 and some use 2.7

assume you leave the pistons .016 in the hole (not advised for proper quench) you would be @ 9.75 with 53 cc heads and 4cc worth of valve reliefs. 10.2 if you flat decked it.

as other have said, at 10:1 and iron heads you will need to check the dynamic compression ratio with the cam intake valve ABDC number (listed under cam specs on comps website)

dynamic compression will help ensure you don't set up a motor/cam/static compression ratio that will pre-detonate on pump gas or force you to retard timing and lose power

most of the smaller cams match your but i bet they won't bleed off enough compression to run pump gas. remember FORDs original compression number were high as compared to actual. Also the gas was different back then.

If you want a smaller cam I would think about reducing the static compression ratio a little so the dynamic is acceptable.

play with both calculators with the cam specs you think you want
 
Save
Reply Quote Like Like
Discussion starter · #13 ·
Thanks atitagain for the explanation. If I'm thinking correctly (advise if not), if the CR is lower, say 9.25 - 9.5:1, what effect on horsepower will this have (obviously lower but to what extent, all else equal)?

Also, is this why the head machine shop was asking about what cam I'm going to use? So he could make sure the dynamic compression is acceptable for pump gas?

Thanks,

Allen
 
#16 ·
The difference between 9:1 vs. 10:1 is negligible as far as horsepower goes.

Maybe they wanted to see if your cam would require screw in rocker studs? A hot cam for a normally aspirated engine is generally going to require a higher compression ratio.
 
Discussion starter · #17 ·
Paul1958 said:
BTW I could also just tell you to use this/that cam from a catalog but that is the wrong way to select a cam that will work for your application or driving style. A lot of factors should be looked at when selecting the good cam - especially static CR, dynamic CR (there are online dynamic CR calculators), driving style (street) or power requirement (race), etc. Cam will determine you entire engine's 'personality', what RPM range for power, etc. Are you considering a roller cam?

Paul
Click to expand...
Paul, not planning on a roller cam. I also don't plan to spin this thing very high (maybe on occasion on a flat stretch just to see how she'll run). And again, just street...sorry I answered that in reverse chronological order...

Allen
 
Discussion starter · #18 ·
Fastback97 said:
The difference between 9:1 vs. 10:1 is negligible as far as horsepower goes.

Maybe they wanted to see if your cam would require screw in rocker studs? A hot cam for a normally aspirated engine is generally going to require a higher compression ratio.
Click to expand...
The heads already have screw in rocker studs.

Allen
 
1 - 20 of 64 Posts
About this Discussion
63 Replies
14 Participants
Last post:
patrickstapler
Vintage Mustang Forums
posts
4.2M
members
101K
Since
2001
A forum community dedicated to vintage Ford Mustang owners and enthusiasts. Come join the discussion about restoration, modifications, NOS parts, troubleshooting, VIN codes, and more!
Full Forum Listing
Explore Our Forums
General Vintage Mustang Forum Mod and Custom Forum Want Ads Concours Forum Build Forum