351 Cleveland?

[emarsh]

I just picked up a new FED chassis at Bowling Green and have pretty much decided to race a Ford. At this point I'm thinking of either starting with a set of the RHS Windsor heads or a set of the old 351C 4v heads. Has anyone spent time with the 351C heads? If so, what's your experience with them?

[jfholm]

I did a couple of sets years ago. The intakes are huge and I mean big big. Probably as big as big block Chevy heads. Really good for "Big" rpm, but and here is the but, exhaust side is kind of poor. The way we made them work is machine the whole exhaust side off and bolt on a rectangular block of aluminum and make the exhaust ports raised up, but that is not legal in Nostalgic Dragster.

Now are you going to run Nostalgic Dragster? If so I think you do need to run cast iron heads. If you are building a "fun" dragster go for the AFR Aluminum Windsor heads. They are really good heads. Get them before you buy too many parts and pull a port mold off the intake and exhaust port to see where the CSA is so you can build your engine around them or at least know where you have to modify them to make them work for your RPM range.

John

[emarsh]

I will be running a nostalgia dragster and so yes, I need to run iron heads. Otherwise I'd be looking at some of the fine aftermarket alloy heads out there. I have found people that sell the high exhaust plates - so the question is, what can be done with the intakes?

[jfholm]

Do you have PipeMax? Figure out what RPM range you are going to run and then calculate the CSA you need. Pull a port mold off of the head and calculate the CSA you have. On one set of the heads I did we ended up filling the bottom of the port to get the CSA and port volume down a little. I cannot remember what they were but do know they were way too big for what we wanted to do. Maybe if Tom Vaught is around he can shed some light on it.

If it was me I would probably consider these heads from World products. They come in either 180cc or 200cc intake runners and are cast iron. The 200cc intake runners are what I would start with.

John

[Greg]

You can buy tongues to fill the bottom of the intake port, I'm not sure if they would be within the rules for what you are using the heads for. Massive improvements to be had by fitting them though.

On the exhausts, even the gasket style plates which block the bottom of the exhaust port are worthwhile. I know one person who wasn't allowed to fit anything to the port tack welded them to the headers so they just slid into the port when you fitted the headers.

[emarsh]

So far as I can tell, I can do most anything to the head as long as they are cast iron without raised port runners on the intake. I'm attracted to the old 4v Cleveland heads because they have huge valves (the '69 Boss 302 had valve sizes of 2.23" and 1.7") and ports. I realize that they won't pull well down low but if I can get somewhere in the area of 370 cfm on the intakes that should be good to 10k on a 400" motor.

Back in the '70s NHRA deemed Clevelands sufficiently superior than the Chevys that Ford pro-stockers had to pull more weight but they still won races. I understand that NASCAR also outlawed Cleveland heads. Seems to me that says something about the potential there - but then again they are a forty year old design. (Come to think of it, the SB Chevy is a 55 year old design though).

I've seen some flow charts for the inserts and while velocity is increased it seems that airflow is decreased. But this is really all speculation until I get some heads and put them on the flow bench and see what I can come up with. I guess that means that I need to get my flow bench completed first tho. ???

[jfholm]

Total air flow is not always the answer though. If the head flows 400 cfm and you engine will only "use" 300 cfm then the velocity is usually way slow. That is one reason to have some of the programs like Pipemax and Engine Analyzer Pro.

As an example I just put together and example of a 400 Cleveland engine that would make max HP at 9000 RPM and the engine would want 456 cfm.

Your intake port CSA would also need to be 4.00 square inches and the exhaust port CSA would need to be 3.00 square inches.

You would also need to have around 1300 cfm of carburetor.

I hope this will give some guide lines in your efforts if indeed you want to build a 10,000 rpm engine.

John

[emarsh]

I'm not really looking for a 10k engine per se - I believe that the head is where you start and then other things follow from there. So the engine speed will be driven by the amount of airflow as well as just plain physics (i.e. piston speed). The class rules require Hilborn style injectors with a maximum size of 2 7/8" at the butterflies.

I will also get myself a copy of Pipemax.

[jfholm]

Good luck Eric, I would love to see a Ford in there.

btw check the rules, in the back of my mind I think NHRA outlawed anything that sticks into the exhaust port. I have not seen a rule book for over a year though.

John

[49-1183904562]

Eric,

You have several options here, do not rule out the 400M 2brl head we often made more power under the curve and a faster car though less total HP with these heads.

What block are you planning on using? the M block has a .9?? taller deck alowing for longer Con Rod less angle more RPM. But you need to find a good ford machinest as the main bores need to be ruduced to cleavland size or you wont keep bearings in them. I think CVO made a block back in the early 90's for nascar with the reduced main journal.

Just some thoughts (been a while since i played with this combo).

Rick

[emarsh]

Rick,

At this point I'm thinking of a 4.125" (plus possibly .080) Dart block with the 9.5" deck and the longest rods that will fit. I'll have to do some research to see what is available in the way of a crank. A 3.6" stroke would be nice.

I'd not thought about the 2V heads. I was under the impression that they are good for the street, but on the small side for a race motor.

[coulterracn]

I have a set of 70's 4v Cleveland heads I'm doing for an 80's Mustang. I can use some modeling clay to reshape the intake port and give you some flow numbers.

I found some info on-line where epoxy was used to reshape the floor and pushrod side of the intake port. Flow numbers were well worth the effort.

I worked a set about twenty years ago. We welded the exhaust ports, gave them a good SSR, raised and rolled the roof. The modified ports were larger than the original OEM port.

Ray

[emarsh]

[49-1183904562]

Eric,

Was not sure about the class if you could use after market castings, If you are game for epoxy the 4v head is the way to go you will just struggle on the exhaust side. got any pics of the chasis yet?

Rick

[emarsh]