250 build

[pmuller9]

I would go with the forged pistons and never have to worry about the short block again.
You can change rockers at a later date if you want to.

If you go with the JE piston would you consider using the longer 300 six rods? (Pre 1969)

 

[cr_bobcat]

I would 2nd the longer rod route with the good piston. Bulletproof bottom end is more important. And like pmuller said, rockers are easy to change later.

 

[69stang_250]

No, I am sticking with the stock rods. I would go that rout, but it cuts into my budget.
I am going to get him to polish and shot peen the rods I have and I guess go with the forged Pistons.
Plan on contacting rocker arms unlimited to see how much a 1:6 rocker assembly will run. I have the stock non adj rockers laying around, but honestly I would hate to put them on this engine. If their sets are too much, I may throw them back on though. We will see.

Here is a good question for y'all. What do you guys think about running a Holley 670 street avenger on my build?
From what I have read they are nice crabs and I think it may be a nice add to this build. The vac secondary is what I am thinking will help it run good on the engine.

 

[cr_bobcat]

RAU wants $400 + exchange for the 1.6 rockers. So if you have a set of adjustables to provide, it'll be $400+S&H. If you have a set of non-adjustables it's $425+S&H. No exchange at all will run you $450+S&H. At least this is what they quoted me maybe 2 weeks ago. This is for the rebushed 1.5 adjustable rockers. This just seems really steep. I could understand $400 for a new set of aluminum rockers, but not for a worked over old set that you still need to provide a core for...

They list another part number that I asked about but they haven't answered at all. Not sure if the guy has been out or what. Let me know what you hear if you do try to talk to them though.

 

[69stang_250]

Do they sell the rockers only? If it's just re bushed rockers I'm gonna talk to a guy and see how much it cost to make a set of 1:6 rockers for ours. Do y'all know if they use stock rockers or another rocker for them?

 

[cr_bobcat]

I believe it to be the whole kit and kaboodle: rocker arms, rocker shaft, springs, pedestals. This is what I got as a response:

"Hi Steve, yes we have the F44 I6 Rocker Arms Assy Stock Ratio 1.5 And also we have a High Ratio 1.6
The price for the 1.5 is $210.00 + S/H Exchange (Hard Chrome plated OEM shaft, bronze bushings, re-face contact tip and new screws.)
The price for the H/R is $399.00 + S/H Exchange."

So they want another $50 or so beyond what Mike was charging for these through the CI website. He must've worked out some sort of pricing deal with them or something.

 

[drag-200stang]

I have a set of RAS 1.6 Al roller tip ,the rockers are heavier than stock. I figure that more spring will be needed to control them,I may thin them down some. the bronze bushing and chrome shaft will help with galling the stock are prone to. I have been told that the roller tip does not roll back and forth across the tip but spins in one direction sliding half the time, makes you wonder.

 

[69stang_250]

If I did roller rockers I would go with yella terra honestly. Looking at how much it cost for stock parts I can see why the price for high ratio rocker assemblies cost so much. I mean just for stock replacement parts to rebuild: new oem shaft 26.79 on RA and 66.99 for a melling shaft. 9.70 ea for adjustable stock rockers at RA. I can't find them anywhere else. then you take their time and how much it cost to run the business. $210 for stock is not bad at all if they are using premium parts. I am trying to find dimensions of other rocker arms now just to see if I can figure out what rockers they use for the high ratio rockers.

 

[falcons99]

Please keep updated information coming as you can, I am enjoying this build and learning a lot. :thanks:

Dave

 

[69stang_250]

Oh don't worry. I update this as I go or if I have any questions. It's gonna be a little while before I get any more pics up though. 4-6 weeks till I get the head and intake back.

I am very glad you are learning and enjoying the build 8)

 

[69stang_250]

Hey there guys, So I have been running some numbers pertaining to my compression ration and all that good stuff.
With the following specs:

Bore: 3.71
Head CC: 58
Piston Deck: .025
head Gasket: .050
255 piston VR: 1.5 cc
Cam: CS 274 110LS
Statis CR: 10.45
D CR: 8.26

1. Will that CR be too hard on a cast 255 piston?
2. is that dynamic CR too high for 91 premium pump gas?

Now with these specs:

Bore: 3.71
Head CC: 58
Piston Deck: .025
Head Gasket: .050
255 piston VR: 1.5 cc
Cam: CS 280 108LS
Statis CR: 10.45
D CR: 8.19

1. Do yall think this cam would be ok on a street car, considering the RPM range is the same as the 274 cam?
2. Each of these are with the cam installed straight up. Would it be better for me to lower the compression and then advance them the 4 degrees that is recommended? or keep the CR and go straight up?

Thanks guys.

 

[pmuller9]

The 280/108 cam increases the .050" valve overlap by 11 degrees over the 274/110 with not much improvement in DCR.
Since the heads are being ported the 280/110 would be a better match and you should be able to make over 300 hp
The overlap would be 11 degrees instead of 15 which is tolerable for street use and the DCR would be lower.
You really want the DCR just under 8:1 so the ignition timing and gas octane is less critical.

The engine will easily pull to 6000 rpm which can be a problem for the cast pistons on the short stock rods.
I just missed a set of C5TE 300 connecting rods on ebay for $12. I would have snagged them for your project. Oh well.
They are the 1964-1968 300 rods without the squirt holes in the big end and also have the smaller .912" piston pin hole.

You are looking at making horsepower with the aluminum head so install the cam straight up.
The straight six has plenty of low end torque to spare.

 

[BCOWANWHEELS]

how often does a main seal go bad ? never unless theres a lot of blow by.

 

[69stang_250]

Update:

Just got off the phone with the machinest about my head and the guy told me hasn't even gotten around to looking at it yet. So, I guess I will be talking to someone else for the rest of the engine.
Also next week I will post some pics of the the mustang. The body shop has done a great job on it so far.

 

[drag-200stang]

If I can get anything done for me in six weeks, I am happier than a lark ,even happier if they do not wreck it.

 

[RichCreations]

Update:

Just got off the phone with the machinest about my head and the guy told me hasn't even gotten around to looking at it yet. So, I guess I will be talking to someone else for the rest of the engine.
Also next week I will post some pics of the the mustang. The body shop has done a great job on it so far.

I would call him back, and say never mind, go get it, and take it to loyd in oakley... You will likely save a fair amount of cash as well...

 

[69stang_250]

I told him I will give him two weeks. I will be calling loyd up tomorrow and give him my laundry list of stuff.

It may just be me, and please correct me if I am wrong in this thinking, but there was a really good friend of my dads that did his machine work. He was the only machinest for 45 minutes to an hour in the area I grew up. This guy did everyone's stuff in the area including the dealerships in the area, and I remember him saying many times that he will not let anything stay in his shop longer than 2 weeks. This guy was always busy and hired help when he got to needing it. Now with that, if you have work backed up 6 weeks or longer, it's time to hire some help and teach the younger generations.

I am not saying that to knock the guy, but to me, he is behind on his work.

 

[Econoline]

Well those days are gone around here. And sure, there's still a guy who is the best and he's cheap, and he does everyones stuff, but he can't control what's coming in and God forbid there's a problem with something and heads start piling up. B/c he said he'd do someones engine or whatever. A good machinist is worth more than a fast machine shop but the speed varies so much depending on the work load.

I hate to rush a machinist, but then again it depends on who you're dealing with and what you're paying

 

[RichCreations]

Well those days are gone around here. And sure, there's still a guy who is the best and he's cheap, and he does everyones stuff, but he can't control what's coming in and God forbid there's a problem with something and heads start piling up. B/c he said he'd do someones engine or whatever. A good machinist is worth more than a fast machine shop but the speed varies so much depending on the work load.

I hate to rush a machinist, but then again it depends on who you're dealing with and what you're paying

Very true! years ago, everyone who drove, at one point needed a machine shop, now days cars are disposable, and almost nobody "rebuilds" anything, so the shops are dying out... When you find a good one, that does not BS you, that gets things done when they say, and done right, keep him, tell your friends about him, do whatever you can to help him keep the doors open, or he too will be gone...

I only made the comment about going to a different shop, as OP and I already talked about it in a different thread.

 

[69stang_250]

i think the thing that got off with me about this machinest is that I dropped the head off almost 4 weeks ago and he told me it would take 6 weeks at the max. Each time I have called the guy, he can't remember who I am and told me once that he doesn't have anything in his shop for a 250 inline 6, almost arguing with me about it. And when I talked to him last he tells me that he hasn't even started on it yet and would be about 5 weeks (from yesterday) till it would be done. I understand stuff happens with other jobs and some people start rushing their builds and stuff, but if that happens, follow up with your customers and let the know what is going on. I mean that is general curtesy.
Maybe I am expecting too much out of the guy, but I have not been rushing him at all. I have just been keeping in touch and seeing what the progress has been. Thus far, it has been none.