Help me build my 351C-2V

AustinCobra said:
Guys, talk to me about valves. The stock valves look pretty good. But I've head a number of people say ditch'm. Here are the specs on the 280 Comp cam. Can I keep the old valves or do I need Stainless? Also the machine shop mentioned something about new hardend seats for the exhaust side due to the current use of Unleaded fuel. They said the unleaded could burn out the existing cast exhaust seats. Is that B.S.??

Specifications:
* Advertised duration: 280 intake/280 exhaust
* Duration at .050 in. cam lift: 230 intake/230 exhaust
* Gross valve lift: .530 in. intake/.530 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 2,000 to 6,000
* Mild rough idle
Not B.S. but you also don't HAVE to use stainless valves. The multi-groove valves were known to drop valves, that's the reason for avoiding them. Comp Cams claims they solved the problem with their valve locks in that situation, your call there, it's your motor. Like I posted before, just order the valves for a 79-82 351M/400 and you'll get the single groove valves if you want to avoid the multi-grooves. Hardened seats are a good investment. Your heads may have already had induction hardened seats being as they were cast in the early 70's, but the hardening goes only so deep and after 1 or 2 reworkings, it will have been ground off the seats.
 
I'm surprised that the shop would even consider NOT putting hardened inserts in the valve seats. The rebuilder that I've used in the past always does it. I'm also surprised only exhaust. I would think all the seats should be hard. I don't know much about rebuilding, but that's my experience.
 
I got my Ferrea valves from AD Performance and they were about $130 for a set of 16.When I took my heads in the owner of the machine shop told me not to bother with the hardened exhaust seats which surprised me as I figured they would want to do them.If you do go with the single groove valves remember that the retainers are different as well, multiple groove valves use 3/8" retainers and single groove ones use 11/32".
 
I'll have to see if I can find a definitive answer on those factory-hardened seats before I get the shop to cut them out.

As for exhaust vs. intake valve seat, the shop explained that it's the exhaust seat that is exposed to the extreme heat of combustion when the valve opens. The intake valve seat, on the other hand, has cool air passing over it from the induction system and doesn't suffer the extremes the exhaust side does. Heck, I was physics major at one time in my life. It made sense to me. But that ain’t say’n much. :shrug:
 
Concerning the heads with induction hardened seats -- the hardening only goes a few thousandths deep, like I posted before, after one or two valve jobs, the hardened iron is ground away, leaving the seats the same hardness as the rest of the head. If the valves you now have are sunken into the seats, it's a good bet, you'll need hardened seats installed. Or you can do as I do, on my 68 Merc's 390, just mix in lead substitute and skip the hard seats. I did a cheap overhaul on the 390 two years ago, the heads were perfect, after 34 years and 60K miles, all they needed was new valve seals. :D
 
A couple things I've learned since this thread originally went up.

While the 2V heads are fine, the chamber shape isn't the best for high performance use. If you want to keep the factory cast iron appearance, Aussie 302C heads are an option. They have a smaller "quench" chamber that raises compression while also reducing the chances of detonation. Powerheads sells 302C heads with CNC porting and big valves installed.

While the cast iron heads are good, if you are looking for high performance you should consider aftermarket aluminum heads. CHI and AFD are good sources. By the time you get cast iron heads ported, valve job, pressure tested, etc. aluminum heads are close in cost. Plus aluminum heads are lighter and have improved runners and chamber shapes.

There are a couple recent header related threads on the network 54 forum.
http://www.network54.com/Forum/thread?forumid=119419&messageid=1123863347
That one is related to 4V Cleveland builds, but good info.
 
Thanks for the links.

I find the whole process of rebuilding an engine, which (for me) involves trusting a machinist to do it right and selecting the ideal components from a seemingly endless variety, rather unsettling. I don’t like the idea of spending real money on a custom rebuild that comes with little or no guarantees. Is this really the best way to get a quality build? Aren’t there companies out there that offer already rebuilt high performance engines, or engines built to suit (with aid of their professional experience), with a guarantee at a reasonable price? Considering the hassles and money involved, this is one area that I’d prefer not to learn things the hard way.
 
Platonic Solid said:
Thanks for the links.

I find the whole process of rebuilding an engine, which (for me) involves trusting a machinist to do it right and selecting the ideal components from a seemingly endless variety, rather unsettling. I don’t like the idea of spending real money on a custom rebuild that comes with little or no guarantees. Is this really the best way to get a quality build? Aren’t there companies out there that offer already rebuilt high performance engines, or engines built to suit (with aid of their professional experience), with a guarantee at a reasonable price? Considering the hassles and money involved, this is one area that I’d prefer not to learn things the hard way.
I would say that if you are building something common and don't care about collectability - no. $$ says go with a crate motor for a 302 build, for instance.

You won't find a crate Cleveland, though. I want one because I think they are cool. I'm willing to pay the price - eventually. :D
 
Well free advice always being worth what you paid for it (note: thats nothing... :D )

IMHO:

Any basic rebuild kit from a reputable manuf will be ok, but that being said talk to your machinist/builder because they usually have a manuf that they know and like (tolerances, fit, finish, etc... they know a particular brand, you would be foolish not to listen to their advice)

Now beyond that... (again in my opinion)

- There is no better intake for the money than the new edelbrock perf rpm. ( read p-e-r-i-o-d) Unless you have a blue thunder in you hand...but they are hella-spendy

- Avoid pop up pistons as they impeed the flame front, if you need compression mill the block to zero deck, or even minus ten... and mill the heads if thats still not enough, you need the squish to generate turbulance to avoid detonation and hot spots.

- Install an oil line from the guage port just above the oil filter that runs around to the port on the top of the back of the block, this feeds fresh high pressure oil to the rear mains that can sometimes get starved due to the lifter galley being fed first. This costs about 2-3 hrs and 15-20 bucks worth of hardware and protects your 2-3-4-5000 dollar investment.

- Try to get the compression up to 9-9.5:1. This is good and safe, but still yields good power.

- If you really want 350 ponies, get a stroker kit from SCAT they can be found for about 16-1700 from strokerkits.com, flatlander racing, chp, paw, etc... do a google for "351c stroker kit".
This will yield 383-390-408 inches and get you MOUNDS of torque due to the added displacement. (you were going to spend money to have the old parts resized, shotpeened, balanced, etc anyhow... these come all ready done) So think of the cost in that context...

- If you can save 1200 and want to bolt on 50hp + get a set of the edelbrock perf rpm heads (bare) they are like 1000 ea complete... spendy but nice. Just an idea... 50+ horses is 50+ horses...

Just .02 from the cheap seats.
Dave-
:flag: :nice: