A
Anonymous
Guest
I'm finally getting started on a 250 build. The finished product will be a '73ish US 250 mated to a 2V head with a standard tranny. I have a load of questions as I start thinking about all my options and I'm especially liking the sleeve idea. I've always liked utilizing "factory" parts as they can typically work as well or better than their high dollar "performance" counter parts and they can usually be sourced at a much reduced dollar amount. Before I start my search for rod and piston combos I thought I would try and get the specs down and figure out how to measure some of these things. Here are some of my questions and thoughts:
Stock 250:
Deck height - 9.469" --- measured from the crank centerline to the top of the deck. I always thought deck height was the relation between TDC of the piston to the top of the block?
Rod Length - 5.88" --- measured from the crank centerline to the wristpin centerline.
Pistons - Not sure of the stock bore size, It's not 1.505" is it(seems awefully small)? How do you measure or verify how tall the piston is from the wristpin to the top of the piston? or total piston height from the bottom of the skirt to the top of the piston. Is a shorter piston better? What would be ideal? How about, where do you want your rings in relation to the top of the piston or in relation to the wrist pin?
Bore - What is the stock bore size of a 250? How far oversized can the block be bored? What size of sleeves am I looking for?
How far below the deck do the pistons need to be?
OK, a couple of more questions and I'll quit,... for now,
Where do I source my cam from? Do I really need to pay for double springs made specifically for the six or can I find 302 springs that will work
satisfactory and still perform the way I want. I don't want a full race cam that only runs under full throttle but I want it as racey as possible without haveing to spend a ton on the head. The plan is to use the SI stainless valves. I have a set of adjustable rockers but would like a 1.6 or 1.65 ratio. Can I achieve this without going roller? If I go roller, do I have to buy yella terra or can I find a set off of ebay made for an eight? I see them pretty cheap all the time(around $100, not $500).
Bearings - O-Rielly didn't even list a rebuild kit for the six. Can I source these by size? Not .010 over, but by the width and main diameter.
Same question for the cam bearings.
I know I can buy all of these things ready enginered for the six, but my thinking is to use as many "budget sourced" materials as possible. I know there will be things that require my wallet to engineer but if I could eliminate a few of these things it might help getting to the end result.
All thoughts welcomed...Dave
Stock 250:
Deck height - 9.469" --- measured from the crank centerline to the top of the deck. I always thought deck height was the relation between TDC of the piston to the top of the block?
Rod Length - 5.88" --- measured from the crank centerline to the wristpin centerline.
Pistons - Not sure of the stock bore size, It's not 1.505" is it(seems awefully small)? How do you measure or verify how tall the piston is from the wristpin to the top of the piston? or total piston height from the bottom of the skirt to the top of the piston. Is a shorter piston better? What would be ideal? How about, where do you want your rings in relation to the top of the piston or in relation to the wrist pin?
Bore - What is the stock bore size of a 250? How far oversized can the block be bored? What size of sleeves am I looking for?
How far below the deck do the pistons need to be?
OK, a couple of more questions and I'll quit,... for now,
Where do I source my cam from? Do I really need to pay for double springs made specifically for the six or can I find 302 springs that will work
satisfactory and still perform the way I want. I don't want a full race cam that only runs under full throttle but I want it as racey as possible without haveing to spend a ton on the head. The plan is to use the SI stainless valves. I have a set of adjustable rockers but would like a 1.6 or 1.65 ratio. Can I achieve this without going roller? If I go roller, do I have to buy yella terra or can I find a set off of ebay made for an eight? I see them pretty cheap all the time(around $100, not $500).
Bearings - O-Rielly didn't even list a rebuild kit for the six. Can I source these by size? Not .010 over, but by the width and main diameter.
Same question for the cam bearings.
I know I can buy all of these things ready enginered for the six, but my thinking is to use as many "budget sourced" materials as possible. I know there will be things that require my wallet to engineer but if I could eliminate a few of these things it might help getting to the end result.
All thoughts welcomed...Dave
