Pipe size, vavles and things

[Anonymous]

Hi all,

Couple of questions for the forum.

The car, 68 200ci 3spd 3.03 tranny 7.25" rear WCY-E--I think 3.00 gears

Goal,
Streetable power for a daily driver
To and from work, weekend cruises, a little light to light if I can find a ricer interested

Immediate Project plans--
Direct mount Holley 5200
Clifford dual out header, port divider
Cam--Mikes 264/274 112 lobe
DSII
Valve job on head
Complete suspension/steering rebuild


Future Project plans--
T-5 conversion
Mike's roller rocker arm


Questions--
Is 2.25" pipe with an H pipe too big for dual pipes? Summit has a set for 130.00.

Do I need a double roller timing chain?

Which of Mike's valve springs do I need to prevent valve float?

Is the 5200 going to be enough carb? Tom says it is 270 CFM at 3.0" vacuum. I like the progressive nature of this carb. I would like the 3 1bbl webers with the offy intake but the carbs are out of my price range.

My head is a 67 casting I think C7XX. I plan on following Doug's web page and the various sticky's directions and doing my own port, polish and deshourding of the valves. Having it machined for the larger valves and installing Mike's stainless steel 77-83 valves.

I want to thank everyone for your time and advise. My car is running right for the first time in the 2 plus years I've owned it thanks to the forum. I've correctly set the timing, fixed the dual vac dizzy to advance correctly, solved carb vacuum leak problems and fixed the auto choke on the 1940 Holley carb. She purrs. Now that I know that I don't have to put up with hard starts, hesitation, rough idle, running hot and all the other problems I've had, I really enjoy my Mustang and look forward to increasing it's performance in the future--with the forums help of course.

Bob

 

[Anonymous]

Hey guys,

I know I'm long winded but if you could just answer the question about the exhaust size and the carb CFM with the headers and the 264/274 112 cam I would appreciate it. Mike is waiting on my parts list and I want to make sure I order the right stuff. I want to do a cam change with these upgrades in mind.

Thanks, I know the forum won't let me down.

Bob

 

[CZLN6]

Howdy Bob:

Sorry for the delay. It sounds like you're just a little anxious to get started.

"Questions--"
"Is 2.25" pipe with an H pipe too big for dual pipes? Summit has a set for 130.00."

Answer- A 2.25" dual exhaust system is a little on the over-kill side, but would work. I'd be a little more concerned about the added weight and longivity of this system. A 2.25" single system would be more then adequate for you stated purposes, be lighter, and condensation would be less of a problem. Probably cheaper too.

This system may show a slight advantage over a smaller system at higher rpms. It could show a slight loss at lower rpms. Where will you be driving most?

"Do I need a double roller timing chain?"

Answer- No, you don't "need" it, but it is a good idea. If you hope to have reliable valve timing past 30,000 miles on this engine (and you should) a double roller timing chain is necessary. These engines came from FoMoCo with the cheaper chains, and many lasted for a great many miles. If all you want is a lo-po chugger, you don't need the dual roller. It you want consistant performance, consider it essential. If I were cutting corners or pinching pennies, this would not be where I cut.

Which of Mike's valve springs do I need to prevent valve float?

Answer- Know that the stock, '78 & later springs are rated at 150 lbs open and 54 lbs closed. These springs, shimmed .030" work quite well up to about 4,500 rpms. If you lighten the valve train by backcutting the intakes, using a one piece retainer and a set of roller rocker arms you will lessen the spring load requirements. If you use adjustible rocker arms you will decrease the chances of pumping up a lifter. You may not need special springs to meet your need. If you do you can always add them later without removing the head. Spring pressure beyond what you need to contol the valves will just accelerate wear and tear.

Mike's cams come with alot of lift, especially on the exhaust side- probably more than a log head can use. The lift may require a different spring to avoid coil bind. I'd check with Mike. If he knows, he'll tell you straight.

"Is the 5200 going to be enough carb?"

Enough? The H/W will be a darn site better than your stock one barrel. Will it give you maximum performance? No.

I'm glad to hear that you are planning to mount the carb directly to the log- no adapter. But, you will get a more favorable, even mixture distribution if you can, somehow, orient the carb so that the throttle shafts are parallel to the crankshaft.

IIWY, I'd build the log so that I could change my mind, if I wanted to, in the future. The Holley 350 is a great carb for this application. The only advantage to the H/W, properly tuned, would be at idle and possibly at low speed transitions. Properly tuned, the Holley 350 would get almost as good mileage and quite a bit more power at the top end. The 350 is rated at 350 cfm as compared to the H/W at 270.

You didn't mention headers or an exhaust port divider. This should be part of your plan.

Enjoy the journey.

Adios, David

 

[Anonymous]

Thanks for the advise David,

My wife would agree that I'm not the most patient person. LOL

I do have a dual out header, is Cliffords the only place to get the port divider? Their salesperson that I talked to was very snotty and not as knowledgeable as they thought they were.

Even if it's still their divider, I would like to purchase it from another distributor?

David if the 350 Holley is good is the 500 Holley better? As long as the MPG is in the teens I'll be happy if the performance gain is there to go along with the lost MPG.

New plan,

Find a 77 to 80 flat log head. Great pics in another post of the difference in the size. Thanks Hot 6t Falcon.

Performance valve job, (4 angle grind, back cut SS valves) diy port and polish, direct mount Holley. 350 or 500?

Go with Mikes 264/274 cam, valve train and his dual roller timing chain

Dual out header, port divider 2" exhaust.---Does anyone know where I can get a kit that has an H or X pipe balancer with it. I would like something that I can bolt on then have my shop connect to the headers.

Gotta go duals for the sound, even if I have to make up lost performance somewhere else.

DSII upgrade

What compression ratio should I shoot for if I want to run on 93 octane pump gas? I would like the highest I can get away with without having to go with alcohol/water injection to prevent spark knock.

I'm not doing the bottom end at this time, but if I blow it up then it will be time to swap all the good stuff, that survives, into a late model 250.

What kind of hp am I looking at with these mods?

Again I appreciate your time. I need to send Mike e-mail so I can get some prices on the cam/valve train goodies.

You know I started this with just the intentions of making it run better--I guess I'll stop when I'm broke and my wife has left. No--I can quite anytime I want--really I swear.

Bob

 

[wsa111]

Bob, David has laid the proper ground work. Shoot for 9.5 compression. However if you go to the 250 & deck the 250 block all your head milling will not be ok on the 250, your compression will be way to high. Decide now if you are going to spend all that money on the 77 up head for the 200 & then spend more dollars on a head for the 250 because of combustion chamber size. For the 200 you will need no more than 50cc's in the chamber to get a 9.5 compression ratio, & thats decking the block to .015 or less on deck clearance. You can't stop in mid stream & use the same head on the 250.
The brothers David & Dennis will give you more precise details on the 200-250 deal. They have one of each example.
David or Dennis take over here. thanks William

 

[CZLN6]

HowdyBack:

Williams right on the heads. To get the chambers small enough for a 9.5:1 CR on the 200, you'd have CR way too high on a properly set up 200. You might want to consider your 1st plan for the 200. Use the '67 head with all the mods, but you might want to consider changing your cam plans to Mikes 264-S. It would be a nice upgrade and more compatible with this head. Go to our website, click on the CR calculater and run your own numbers. Given your elevation in MD, I'd suggest a CR goal of 9.5 to 9.7. The cam will help reduce dynamic cylinder pressure. And be sure to polish the chambers. The 5 speed should keep you from lugging it.

All of the flattop log heads are large 62 cc chambers. Your '67 head will have a 52 cc chamber. YOu would absolutely need all of a large chamber to build a 250 right.

The 350 and 500 Holleys are very similiar in performance and tuning the difference would be better performance at higher rpm and WOT. The down side would be low speed stumbles. Much of that can be tuned away, but it would still be a bit of a burden. In this application the mileage wouldn't be too different. The problem will be keeping your foot out of it! (grin!!) The solution is to get both. Drive the 350 daily and to the track. Swap on the 500 at the track or Maxton and enjoy.

Adios, David

 

[Anonymous]

Thanks for the advise William/David you guys are great.

Now to find the right machine shop and get the goodies in from Mike. Can't wait to get started. Hope to see you guys in PA this June.

Bob