Head Rebuild Q's

[Anonymous]

I just took apart my 69 M head and am getting ready to take it to the machine shop. I got a few questions for all ya.
Thinking of performance here:

1 What size valves should have installed in there?
2 Should I get a 3 angle valve job?
3 Should I get the valves back-cut?
4 If the head has not been milled before, how much should I mill off to get a compression ratio of around 9.5:1-10:1?
5 What valve springs and retainers should I go with if I get the larger valves?

I hope that this will be a good build up for my car. I plan on getting the log milled to accept a holley 2 bbl. and I will be using a steel-shim head gasket. Just keep in mind my other mods so I can get the best performance with what I have:

comp 260H
D2 w/ MSD
Small dish pistons

Thank you all for all your help with my continued project...

Later,
Paul

 

[Anonymous]

Hello there 65mustangman


Time to do the head up....

In answer to some of your questions:

1. Not sure, others can offer some suggestions on the size...?
2. Most definitely... the valve job is required in my opinion for any I6.
3. Yes, I have always seen a positive opinion on adding this angle to the valve job....
4. Best to CC the chambers and find out where that head resides now in terms of the amount of metal to remove, then go for the cut to get the right CR... I cannot give you figures, I let the machinist do the math for the cut, also it might depend on the amount needed to get a true cut, I ended up decking the block than cutting a tad less on the head.
5. Your machinist will get springs, guides and retainers to match the new valve size... my first suggestion would be to get the Comp kit for that cam, that is what I would do.

First determine the Valve size you want to try... then determine current CC and you can go from there.

I got my final CR around 9.6:1... that is with the approx final measurement using a Fel-Pro gasket, I can opt for the metal gasket as I have one, but I wanted to be able to use Composite in case I ever cannot get another metal one. I am also running a cam in the range you are looking, your engine internals are very similar to mine...

 

[Anonymous]

Hey there Jimbo!

I like the head. Some of those studs look like they are going to be a pain to get out but I'll manage. It will be nice when I get done with it, hopefully. I'll try to get pics of the build up as I go so others can have a refrence. I can't really do to much on it all at once now. (College student income isn't all that great!) But I do want to start to work on it and get it ready for the machine work.

I guess I'll have to go into the machine shop next week and start talking some business! I think that there was someone on this board that was a machinist here in SLO.......

Later,
Paul

 

[Anlushac11]

I just took apart my 69 M head and am getting ready to take it to the machine shop. I got a few questions for all ya.
Thinking of performance here:

1 What size valves should have installed in there?
2 Should I get a 3 angle valve job?
3 Should I get the valves back-cut?
4 If the head has not been milled before, how much should I mill off to get a compression ratio of around 9.5:1-10:1?
5 What valve springs and retainers should I go with if I get the larger valves?

I hope that this will be a good build up for my car. I plan on getting the log milled to accept a holley 2 bbl. and I will be using a steel-shim head gasket. Just keep in mind my other mods so I can get the best performance with what I have:

comp 260H
D2 w/ MSD
Small dish pistons

Thank you all for all your help with my continued project...

Later,
Paul

1)According to a write up on performance that was linked to here once upon a time, the stock late model US sized valves are suffecient. On a log head due to breathing restrictions you can run as big as 1.84" intale and 1.55" exhaust BUT THERE WAS NO POINT IN DOING SO. By doing so the author lost low rpm throttle response for appreciable gain in performance.

2)Yes 3 angle valve job could almost be considered the standard nowadays.

3)Depends on the cost. I recommend gewtting them if its within your budget. In some of the stock classes where racers arent allowed to change valve diamater back cut valves are the loophole to goet more HP out of "stock" valves.

4)Generally you can mill about .060" off the head to raise compression by one point. BUT you need to make sure the head hasnt been milled before.

5) That is dependent on the cam. Whatever cam you decide to run I recommend using their cam kit which has the lifters and springs and retainers matched to the cam.

Your setup sounds similar to what I plan to run. Hope it runs good!

 

[CZLN6]

Howdy Paul:

How exciting.

Yes to 2 & 3. These two will do more for flow than almost anything esle you will do.

#1- The stock size for later heads is 1.75" intake and 1.39" for exhaust and you should at least go to the larger intakes. Larger exhaust are very pricy and are of marginal benefit, unless you do some porting. My brother and I are using intake valves from the 144 engines in the exhaust for a slight increase in size at 1.467". I have heard that Clifford's is stocking a 1.5" SS exhaust valve in our stem diameter and length. Don't know the price. The other option is to buy a set of Chevy 1.5" and cut them down to our size.

The small bore diameter limits the use of anything larger than 1.75"intake and 1.5" exhaust.

The "M" head typically has a stock chamber volume in the 62 cc range. A cut of .050" will reduce it to the 52 cc range of a '68 and earlier head. We use the ratio of .010" = 2 cc. But, as already mentions, the only way to know for sure is to measure the volume after each cut. You can safely mill these heads up to .090". To get to your desired CR of 9.5 or 10:1, you're better off with a combination of decking the block, pistons and head. If you mill your head to the max now, you will likely have too much CR once you do the block.

Given your set-up, and assuming they are in good shape, your stock springs shimmed .030" and stock retainers will be adequate to 6,000 rpms. Using heavier springs than you need to control valve float simply add stress and hasten wear. We like using early 260 V8 one piece retainers. They are lighter and slightly shorter. They are also scarce. Later 260s used 289 size valve stems and a larger retainer. It's got to be the early ones.

I am also checking out using one piece retainers from a 4.0 V6, FoMoCo.

Be sure to get an exhaust port divider fitted and installed before milling. Also look to the oil transfer slot between the head and block. The head gaskt will help you to locate it. The stock head has a slight relief and a necked down head bolt to help with oil volume.

Enjoy the journey.

Adios, David

 

[CZLN6]

Howdy Again Paul:

I just got this info. SI Industry's in So Cal makes stainless steel valves for our engines. They run $9.90 per valve (Ouch!)

Part numbers
SEV-3007-S Ford Intake 200/250 6 cyl 1.760H
SEV-2530-S Ford Exhaust 200/250 STR 6 1.50

I'm still checking on the 4.0 one piece retainers.

I hope this helps.

Adios, David

 

[Anlushac11]

8)

Found this

http://www.sivalves.com/

 

[Anonymous]

Hey, just received the SI stainless valves mentioned and bronze valve guides from them 2 weeks ago. Paid 7.95 per valve, all total came to 119.00 with guides and shipping. Received them in 2 days. My machinist talked me out of the bronze guides though. He said you have to run them real sloppy.

Gary

 

[addo]

Gary, I'm keen to see an expanded explanation of your machinist's reasoning.

Thanks, Adam.

 

[Anonymous]

Thanks all for the info!

I guess I'll be sticking with the stock valves but upgrade the springs and related hardware.

Time to go to the machine shop to find out how much this baby is going to cost me!


Late,
Paul

 

[Anonymous]

One more question...

Where and what type of valves should I get for the head. I just ordered comp's springs and locks but it is going to need new valves. Old ones are toasted! What company should I look for? Any suggestions?

Thanks for all your help in this!

Paul

 

[Anonymous]

Try the SI valves at the top....

But I am wondering? have you talked to your machinist yet?

The reason I ask is most places can get you stock replacement parts for the rebuild....

I let my machinst buy 90% of the hardware needed for the rebuild, and some places include hardware in their quotes to rebuild heads, as most people don't bring in their own.... unless you are getting an unusual size or special item. I would ask the machinist if it is worth your time to find these parts....

The only parts I supplied to them were the Specialty parts from Mike and some related items.

I was still at a reasonable price for the rebuild.



Just a thought....

 

[Anonymous]

that is a good idea. I already ordered the springs but i really wanted to get the comp springs on it but for the rest i'll see the machineist first.

Thanks for the help.
Paul