250 build

As far as I know there is no one making a windage tray for the Ford 250...I looked for one back when I built my 250. As far as carb choices I would say 600cfm is a good choice...the 250 likes air and with the CI head it should work very well IMHO. Others may have other ideas.
 
I would look at the Quick Fuel HR Series, either the 580 with vacuum secondaries or the 600 mechanical secondaries.
You get 4 corner idle adj. fuel level windows and they are a lot more tunable than most other carbs.

Pistons:

One of the reasons for a custom piston is to save you money on machining cost.
The CH should be closer to 1.63" so less then .010" needs to machined off the block deck.
The bare block deck height needs to be measured.

Also the cylinder bores need to be measured or take a preliminary cut (my preference) to see if you need more that .030" to clean up.
Typically #1 cylinder has the most wear.

You will also need to decide on which piston rings to use (I'll explain later)
and whether or not you want the pin offset.
I would also ask them to limit the dish diameter to 2.5" so there is more piston quench area to match the quench pad on the head.
They usually only leave between a .350" to .400" quench ring around the piston top.

I will call AutoTec Monday to verify a few things.
 
X2 I also think the 600 CFM Holley could be dialed to work well for your 250 and the there is also a couple smaller 4V Holleys in 390 CFM & 465 CFM versions that 465 CFM maybe even better suited for your combo of street and race car. I do happen to have one and was once planing to run a pair of them on a 300 drag engine build. You probably have to make your own windage tray though I think someone is making custom crank scrapers, for the oil pan you likely have to make that also but there used to be some kits you could weld into the stock pans it's not too hard to even build them from scratch if you can weld. Good luck :nod:
 
As far as carb choice goes, i can recommend an Edelbrock 500cfm or 600cfm. The 500cfm AFB has worked great for me, more compact than a Holley which was useful in my engine bay and is easy to tune once you understand the operation.

I reckon 500cfm would be a good choice for your build, however if your going to stretch its legs with some high rpm then the extra flow of the 600cfm may be a good choice (y)
 
I have been looking at the 600 Holley after seeing the vids and reading about mustang geezers car. I figure if his 200 runs great with it a 250 should run good on it as well. The only thing is I would rather go with one just a little too small over one too big. The vac secondaries seem to be the best for street use from the reading I have done. Although, I have read mech secondaries work good with manual trans combos. What are y'alls opinions on this?

Pmuller- that's what I will probably do for the CH of the Pistons. Had talk with the machinest and told him I want to mirror the combustion chamber and make the dish deep enough to allow proper valve to piston clearance, so there is very little if any mods needed to the dish once we moc it up.

I may talk to a local hot rod shop and see if they can weld up my oil pan and fab a windage try. But, how much does the windage try help the engine? I understand it's purpose, but would having an oil pan built up to control oil be sufficient for this type of build?

Back to the carb topic. Which is the most simple to tune? I don't mind having lots of options, but prefer a "meat and potatoes" aproach to things. Which ever I go with will only be on for about a year and then I plan on going MPFI.
 
The valves look like they are deep enough in the head as not to have piston clearance issue but it is always good to check anyways.
With a dish piston if there are valve to piston problems, the intake valve usually hits the inside edge of the dish and not the floor of the dish.

bth_P1020917%5B1%5D.jpg
 
The mechanical secondary carb needs more accelerator pump squirt than the vac secondary but you know for sure the secondary is wide open.
Which EFI system are you looking at?
 
Yes I would think that. With a 3.71 piston and 1.88 and 1.50 valves I figure it would be the inside of the dish that would have any clearance issue. I don't know how deep the valves are in the head, but my log head valves are .400 in the chamber at the peak of the intake valve. The valves do look deeper in the AL head though.

And the answer for the piston ring question is moly rings.
 
Well I was looking at the complete setups from Edl, Holley, and FAST, but I'm thinking about just going with a mega squirt system and building on that. I'm trying to read up and learn more about the set ups and what I would need to build a good reliable system.
 
Intake valve to piston clearance is closest at 10 to 15 degrees ATDC. I don't suspect the valve is out of the chamber at that point.

Please correct me if I'm wrong, as far as I know a 3.71" bore has only 5/64" rings available.
If that is true then going to a 3.736" bore will give you access to all of the racing application ring sets for the 305 Chevy. 1/16", 1.5MM, 1.2MM, ductile iron moly faced top ring, ect....
 
Got some up dates and will post pics soon.

Engine block is bored, honed, cleaned, and all that good stuff. It's just at the machine shop waiting for the head to be done.
main studs and rod bolts installed along with rods being polished and shot peened.

Today got back from caffeine with the local vets and my cam was sitting at the door :D

CSC H-280 LSA110 Now I have a good question for you guys. When finding the Int closing point for measuring dynamic compression, do you use the @.050 duration or advertised?

I ask this because when I put the number on the cam card in the calculator, it throws everything out of whack!
Cam card has 43.5, however, if you use the advertised duration I get 70.

I will be contacting RAU tomorrow about the rockers. I'm trying to stay with 1.6 because .512 lift is in that peak area of airflow.

Also, am going to go with Holley for carburation, but wondering if I should go with the 570 avenger or 600 vac secondary?
I know mustang geezer is using a 600 Holley with his built 200. Any way I go, I will use a vac secondary carb. These seem to good for street use and I can change out springs if I need the secondaries to open sooner if need be.

I'll post pictures tomorrow for you guys.
 
For DCR calculations you use the advertised duration.
70* ABDC is correct if you are going to install the cam straight-up with the intake lobe center at 110* ATDC
Does the cam card suggest the cam be installed 4* advanced?
 
Ok that is what I was wondering.

No it does not say anything about advancing the cam at all, however I think I saw on the CS website that it's recommended.

I am about to get on their website and see if I can find it. If not, I will call them and find out.
 
Yes, I just found on the clay smith website that all of their cams are ground straight up and should be advanced 4 degrees.
 
I don't have one. The set I am going to get is the 69 timing chain set from clay smith. Is there a timing chain set with key ways machined in?
 
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