BIG SIX BUILD-UP ARTICLE BY FTF

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russk

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CNC-Dude and FTF:

I just wrote a (too) long post regarding the 240 vs 300 inch question and it apparently got lost in the "ether", maybe running into the 'Flyer's most recent post.

In any event, I have been under the perhaps mistaken impression that the 240/300 Ford OEM head would not achieve the necessary flow to support a 300+ ci race motor spinning at (say) 7500 RPM. From what the "calculators" say, the head would need to have an intake flow of just over 302 cfm. I didn't think you could get there but given CNC-Dudes recent post and the 'Flyer's great article, maybe (in the right hands) such flow is achievable.

But my interest specifically in the 240 version of the big Ford was primarily based on the Inliner's D/D[ragster} class rules that limits the displacement to a maximum of 260 ci. There are a number of engines that would be good candidates including the 250 Chevy, the 225 Mopar slant six, the 242/258 AMC/Jeep, and the 240 big Ford. There may be others but they don't come to mind . . .

'Flyer, if I get off dead center on this project, I'm sure I'll have (too) many questions to ask and I appreciate your willingness (as well as others on the inline six forums) to share your experience and expertise.

Russ
 

twocron

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Really enjoyed your article on 240/300 buildup. I am gratified to see that someone of your level of expertise appreciates the 240. With the former AMC 4.0 showing what four litres can do,a Ford 240 can at least match their performance. BTW the combustion chamber roof support was said to date back to the Lincoln Y blocks used in the Pan-American races in Mexico in the 1950's,can neither confirm/deny truth of this "engineering legend" but have seen period photos of these heads w/ support studs in area that eppear to be over c/c roof? As an aside six cylinders of anymake but GM are considered a joke @ most NHRA strips,seem to be more tolerated than appreciated;until they kick-a... on the GM's,then its tear downe time,"ya hadda been cheating"etc,etc.
 

'68falconohio

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THE FRENCHTOWN FLYER":1q48wutb said:
This article was published in SuperFord Magazine in 1985. Most of what I wrote still holds true today. Enjoy.

FTF, is there anything in particular about the 240/300 engines that stick out as not holding true anymore? I'm curious. :p
 

F-250 Restorer

Famous Member
Hello, Greg--

Thanks for taking your time to call me for the article. I wanted to let you know what was happening. The editor went with a humorous piece involving my 300, but now wants a 'how-to' article on the 300. I still have the notes from our talk, so you will figure prominately in the article.

I was wondering if you have any photos of a build in process, showing pistons of a 390, or any other type engine. I will, of course credit you with the photos. A PHOTO OF A CROSS FLOW HEAD WOULD BE THE CROWN AND GLORY OF THE ARTICLE.

Kevin Hill
 

THE FRENCHTOWN FLYER

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Hi again. I think the 352 piston is a better choice for the 300. The 390 has a stock bore of 4.050". The 352 has the same 4.000" bore as the 300. If the stock 390 pistons are used then there will be little room to rebore at a later date if cylinder wall damage occurrs. I have a 352 piston we used in the Pinto that my partner cut down using a CNC program that left a dome above the combustion chamber, thereby increasing the compression on this race only engine. For street use just turn .050" off the top of the piston to create a flat top. I think we paid $6 a piece for the cast 352 pistons.

I don't have a photo. I will dig the piston out, photograph it and post it.

Here is the crossflow head:
sr_046-1.jpg


4/17/10 update:
Here is the piston we used
300_352piston_02_2.jpg
 

THE FRENCHTOWN FLYER

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A couple of people have asked me about the cylinder head fixture. I think there are several good reasons to building one for yourself:
1) piston-to valve clearance may be accurately and visually checked
2) pushrod length with aftermarket rocker arms may be accurately established
3) port wall thickness is evident and porting procedures can be planned
4) rocker arm-to-valve retainer clearance can be checked through the lift curve

Here's how to do it. Cut out a head chamber. Leave enough stock to save the head bolt bosses. Install the valves you are using. Install the rocker studs you are using. In this case it was a 240 head with 1.94 and 1.60 Chevy valves and screw-in Moroso studs. Install light checking springs. Then using a band saw or Sawzall make cuts through the ports while saving the mounting bolt locations. It may be necessary to chip away the port with a hammer and chizzle.

head_fixture_02_5.jpg


head_fixture_03_6.jpg


head_fixture_04_7.jpg


head_fixture_01_4.jpg
 
A

Anonymous

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in a previous thread you mentioned for porting advice ..do not remove the step/ledge around the exhaust stem of the exhaust port but you were not giving any reason as to why ? thanks
 

THE FRENCHTOWN FLYER

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sam2007":3rddogy6 said:
in a previous thread you mentioned for porting advice ..do not remove the step/ledge around the exhaust stem of the exhaust port but you were not giving any reason as to why ? thanks
It hurts hi-lift flow numbers.
 

62RatRod

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I just want to say I love this website lol my dad bought me that same magazine off eBay a while back when I started building my 300 for my 62 f100. Does anyone know what the biggest cam you can put in while using the Chevy 1.7 rockers without having to machine the head too much? My machinist is supposed to be ordering my cam for me but I haven't told him about the rocker arms yet. He can machine down the spring perch for taller springs and put in new rocker studs if he needs to. I just kind of wanted to look like I know what I'm talking about when go to ask him about it. Any advice or know how would be very appreciated :wow:
 

Luckyman

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Chev rockers are for use with a stock cam. If you are going to use a different cam that will take the place of using the chev rockers. I would not use both. It is an either/or situation. The rockers are a budget solution for those with a compatible rocker arm & pedestal setup running a stock or equivalent cam.
 

THE FRENCHTOWN FLYER

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With higher lifts the first limiting factor will probably be valve guide-to-retainer clearance. That assumes you have springs that wont coil bind. Lifts in excess of .600" are possible. On one car with a cam with .6-something lift I am using the 1.75 rockers that puts me over .700" lift.

Be sure to check out the FAQ addressing all the clearances you need to address for mods like this. Good luck.
 

62RatRod

New member
Thanks for the info, Ill talk to my machinist about it as well cuz I dont think he's ordered a cam yet and I was wanting soumwhere close to .600 lift. maybe a little less and I gotta get new pushrods anyways so I'll just get them 3/8 pushrods if the Chevy rocker arms will work with them.. How much power could I expect naturally aspirated with .600 lift, bored .040 over, 2.02 intake 1.85 exhaust (or soumwhere around there), a 3 angle job, gasket matched runners, and 8.8 cr? I know that's a lot to account for but you used to race these bad boys right? :beer:
 

THE FRENCHTOWN FLYER

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62RatRod":1cr7pnvh said:
...you used to race these bad boys right? :beer:

...still racin' - every summer.

Depending on the rest of the build 250 - 350 HP is quite attainable with a .600 lift cam and big valves.
 

62RatRod

New member
Awesome (y) I'm thinking about building my truck for LSR.. There's a guy on another forum that has a bada$$ long bed uni like mine. He ran like 130 at bonneville with a 301ci y block ford. To compete in the class I'd b in if I lift it naturally aspirated I'd have to do soumwhere n the 160s : :hmmm:... Another quick question, may sound dumb, but it was brought up on another forum I'm on. Is there such thing as a commercial block that has more bore spacing? A guy said he had his 300 bored to into the water jackets then sleeved an re bored to like 4.5 in.
 

THE FRENCHTOWN FLYER

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To my (somewhat extensive) knowledge there is no such thing as a commercial block with larger bore spacing. The standard bore spacing on all 300 blocks os 4.480 inches, .100" wider than small block Ford V8s.
 

CNC-Dude

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I wouldn't recommend putting 6 sleeves in a block unless you go to the extreme Bob Glidden did with his Cleveland blocks back in the 70's and furnace brazed the tops and bottoms of the sleeves to the blocks. But then you have to remachine all the machined surfaces to get them back square. Just putting sleeves in 2 adjoining cylinders places tremendous stress on the deck, especially with these thinly cast blocks, much less all 6 cylinders.
 

62RatRod

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Yea I figured it was too good to be true.. I didn't even wanna bore mine but .020 over cuz of how thin the walls looked but 2 of the cylinders were pitted with rust so he did .040. I wish his daughters still worked there cuz they used to port n polish and I know I don't have the hand eye coordination to do much.. How far down the runners should I go when I try to gasket match them? I have a spare head I can practice on that's from the same year model, I think they're '87 castings..
 

THE FRENCHTOWN FLYER

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I wouldn't bother to port match - it is largely a waste of your time. Just be sure there isnt any place the head intake port opening overlaps into the intake manifold runner and the exhaust manifold runner does not overlap into the exhaust port.
 
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