I have a used set of cleveland 2V heads for my 1977 400cid. Already have brand new: Comp Cams 268H, Comp lifters, Comp magnum roller timing chain, Performer 400 (no egr) intake with Edelbrock 600cfm carb. I will buy a set of scorpion pedestal type roller rockers. I will also get a distributor gear valve spring set to match my cam. I will ask the machine shop to grind the little bumps in the exhaust ports then polish them.

Would it flow better with 1.710/2.190 valve instead of the stock size?
What else can be done to these heads to make them better?

Thanks for your advice.

 

i've seen data that shows the 2V's to outflow the 4V's up to about .500" lift. be aware that flow results are easily skewed by the operator, vary from one flow bench to the next, and flow numbes don't necessarily mean HP. the 4V valves in the 2V heads flow slightly better but don't really shine like you might think. the bowls need extensive work to take advantage of the increase in valve diameter. IMO your $$$ is better spent on quality one piece valves(see link) that will not lose their heads, and a little clean up work in the bowls. i think you'll enjoy the 268H 2v combo, especially with the extra 50 inches! http://raceabilene.com/kelly/hotrod/wreck.html

 

Sorry for my ignorance, I really don't understand the extra 50 inches you are talking about. What is it?

Thanks for the link, I don't want this to happen with my engine. I won't buy nothing else than Ferrea stainless one piece valves.

So there is no great results in swaping bigger valves into my cleveland 2V heads?
I don't mind paying a little more on the head job to get a little more flow by using bigger valves, but I want to keep the 2V port size. Does it make sens?
Is it worth the $ to use bigger valves and work out the bowls?

Thanks.

 

the 50 extra is your 400 vs a 351. great results, not really, or it would be a lot more popular. you'd be paying a lot more for a little more flow. is it worth it? some would say yes, if i needed more/better flow i'd order complete alloy heads rather than have all kinds of work done to a set of old castings that could crack any minute. several guys have done the nickel and dime routine and found out they spent almost as much/more on the iron heads than the alloys would've cost. a set of 2V's with a little needed work into them can be cost effective but trying to make them something they were never intended to be can get expensive.

 

Thanks a lot grclark351, I will stay with stock size but first thing I must do is to send my heads to a machine shop to clean them and magnaflux... to make sure their ok. I just bought those heads for $10.50 on ebay, there is a little rust on it.

 

here's a current "for sale" example.
I have a set a 4v closed chambers with ferrea 5000 valves i/e, machined for screw in studs arp studs,comp spring cups,comp 980 dual springs, crower 10* locs and retainers.. Heads are used but still in very great shape. i want to try a set of chi 2v's

Price break down
Bare heads $400
Valves $250
Springs $117
Cups $37
Retainers $75
Locs $45
Studs $32
misc $50
Machine work $200

Grand total $1206

that's a chunk of change to have tied up in a set of iron heads that you don't even want, because you want a set of alloys. i think he'd be one lucky SOB if he gets $500 back?

 

I have a 77 F250 with a 400. I came up with Cleveland heads from a 71 400ci.
They are 2v with some port work.

260He cam and spring kit
True roller timing
Flat top pistons
400 Edel intake
670 street avenger carb
Hedman heders

I am getting 18 MPG

 

grclark I disagree. I've been doing alot of talk with different head rebuilders that have extensive exp with Clevelands. And for the best bang for the buck, and running a reasonbable cam, IE not a race cam. Going to 4v valves is the way to go. Staying around 520 lift and reasonable duration I have been told extensive porting will hurt, cause of low lift flow. Port velocity ect. I opted for the one piece undercut and tuliped stainles 4v valves, with unshrouding of of the valves and slight bowl work. I was actualy talked out of the cnc machining and hand porting wich would make the heads killer for a 550 horse screamier, but I have something alot tamer in mind. This saved me 500 or so dollars that the shop could have easily milked me for. I'm pleased that I went to a reputable head shop and did alot of looking and phone calls before I finaly decided. Thanx.

P.S. those prices are a bit high also. I could have got all those part( better quality) plus 5 axis cnc porting (finished up by hand) from a reputable shop ( 20+ yrs exp with Clevelands) for a just a little more. Go figure.

 

the only part of that list that looks high to me is the $400 for the original heads heck I can buy clevelands from a local junkyard for 150 complete around here, and most will almost give you a 400 core, heck I haev thrown away several myself since I don't like the open chambers on the 2v heads. and where are you going to get some one to do that work plus 5 axis cnc porting for just a little more, Charlie Evans just posted int he classified of another forum that he charges $1475 to cnc port NEW A460 heads and more if they have been used so if they are doing it plus all the parts, and work to rebuild the heads for $1300 then I wouldl be REAL suspicious of them knowing anything and I would want to see unbiased flow numbers from a different operator on both before, and after on a set of 2v heads cause if hte cnc program isn't set up right it will actually hurt you rather than help any

 

http://www.powerheads.com/351c.html
This is the company I was refering to. As far as there flow numbers being accurate, I have seen them refered to in a few hot rod magazine articles and they have always been accurate on there numbers. And I guesse for $1730 you could drop a little more coin and get some alloys. Thanx

P.S. damn, around here you can by 2v heads at the junk yard for $100 all day long, go figure.

 

http://web.archive.org/web/200206100...s/fmotorsp.htm (it loads slow cuz the page doesn't exist anymore)
12 cfm intake and 8 exhaust at .500" is not what i'd call spectacular results for oversized valves installed and bowl work. some of the heads on the chart responded that much to just the bowl clean-up. increase in intake valve diameter, .15"(barely over 1/8"). increase in exhaust valve diameter, .056"(less than 1/16"!!!). i'm going to suggest that the stock valved heads might've responded better to the bowl clean-up than they did to the valves and bowl work? yes, that is what i get from everyone i talk to about porting, that it's easier to to do damage to the flow rather than improve it. like i said earlier, "is it worth it? some would say yes", but i don't think so.

 

Those are some realy poor charts! Anyway i was qouted a 19 cfm increase at .500 on the intake and about 18cfm on the exhaust at the same lift. That might not sound like much, but it does equat to a little more horsepower. All for the same price as stock valves, I got the 4v (stainless onepeice, undercut and tulipped, same as the stock valves I was looking at) Slight bowl work and unshrouding of the valves. But for $675, I supplied the heads, I got the valves, tightanium locks retainers (my valvesprings that match my cam) hardened seats, new guides, hot tanked magnufluxed ect, ect,ect. For what I paid it is hard to get the same power increase from some other mod, except maybe NOS. Anyway I think we could pull up different charts and graphs all day long stating our own beliefs, so I'll let yah now how it runs when I get them back on my 400. Thanx.

 

I dont know alot about the 351M/400, but I heard that the heads on the 351's are just 2VCleveland heads? Is this true?

 

yup, the 351M/400 heads are almost identical to the Cleveland 2V heads. a couple differences are that the M/400 chamber is about 2cc's larger(76.2cc/78.4cc) by published data, and the M/400 heads evolved into smogger heads with the addition of A.I.R. passages(emission system). in 75 the water jacket was revised to include more cooling around the exhaust valve. the only thing to stop you from using 2V C heads on an M/400 would be if you wanted to or had to run the A.I.R system. Australian 302C heads are also almost identical to the 2VC heads except for the much smaller "closed" or "quench" combustion chamber(around 58cc's).

 

Responding to the original question; will installing larger valves help? No, they will hurt, not help, your engine. Use the original sized valves but spend your money on a good valve job. Back-cut the intakes, and break the edge on the outside of the exhaust valves. No need to port the cylinder heads except to smooth the angles just under the valve seats.

Cleveland heads flow like crazy right from the factory. If you're going racing, then you can think about larger valves, but if you were racing, you wouldn't be asking for advice on a truck forum.