Fuelie 461X Iron Heads #1

[Bill B.]

I was reading up on the history of the first set of 1961 'fuelie #461X 1.94 int. & 1.50 exh. heads' and was surprised to see Stan Weiss latest flow chart using 28'' of water rating them as the best flowing heads ever made, in (cast Iron) 49 years ago. Hook that up with the legendary Dontov solid lifter camshaft. That is a Very impressive combination. Just think if the aluminum versions of 461X made it to production how this would have made a performance impact back then.

Just reflecting on the good old days.....When there were slow women & fast cars.....

Bill

1961 Black/Silver/Red Int. 283/315 FI
power windows. Frame off 65% completed.
1989 hard top daily driver 165,000 miles

[Mike M.]

Re: Fuelie 461X Iron Heads #1

the local dirt track guys still seek out the 461x heads and pay dearly for them. i agree with your sentiments. mike

[Bill B.]

Re: Fuelie 461X Iron Heads #1

Mike - I see a pair or two on ebay now & then.....now is the time to pick these up while the prices are reasonable. They will perk up any small block. It's amazing how much those Chevrolet engineers knew back then using only a slide ruler and no computers!!!

Bill

1961 Black/Silver/Red Int. 283/315 FI
power windows. Frame off 65% completed.
1989 hard top daily driver 165,000 miles

[Steven B.]

Re: Fuelie 461X Iron Heads #1

I used to run 461X's with a Duntov cam and dual 4's on the '57 with a 4 speed, 3.70 and Atlas Bucron Cheater Slicks. I sure miss those days!

[Clem Z.]

Re: Fuelie 461X Iron Heads #1

they had a larger volume intake port and NHRA s/s racers used to pay big $$$ for them but since the NHRA now allows heads to be ported to a certain CC limit their demand hs fallen. the new vortex head flow much better

[Duke W.]

Re: Fuelie 461X Iron Heads #1

The Duntov cam was not really very well suited to the flow characteristics of those heads as machined by GM, due to the low E/I flow ratio. (The Duntov cam was designed around the early small port/small valve heads for a shorter stroke configuration.) More exhaust duration with an earlier opening inlet valve is required, but GM didn't release that new cam until 1970.

Typical head massaging gets the E/I ratio to something more friendly to equal duration, but the longer exhaust duration of that 1970 cam does no harm.

I heard back in the seventies that 461X heads were sought after by sprint car guys, but with the proliferation of aftermarket heads, which are now legal in most racing venues, I can't imagine why anyone would start with 461X heads on a serious racing configuration.

Recently I saw some flow data on a set of massaged Dart Iron Eagle 215 cc cast iron heads, which have conventional 23 degree valves and straight plugs - about 300 CFM at 0.5" lift and 28" H2O depression. That's big block territory!!!

But with a little work (and a decent set of rods for reliability) these old heads and all other major OE components can turn an OE mechanical lifter 327 into a 7000 plus rev screamer with close to 300 SAE corrected RWHP and decent low end torque, which ain't bad for a basic engine design that is 55 years old and dirt cheap to rebuild compared to anything else with similar power!

Duke

[Bill B.]

Re: Fuelie 461X Iron Heads #1

Duke - I see it as the 461X heads beat the Dart Iron Eagle 215 massaged with equal size valves hands down....Unless your talking about a newer set of heads that didn't make Stan Weiss' 383 page flow test chart.

Check it out links below, and please give me your comments.

http://users.erols.com/srweiss/tablehdc.htm

I appreciate it,
Bill

1961 Black/Silver/Red Int. 283/315 FI
power windows. Frame off 65% completed.
1989 hard top daily driver 165,000 miles

[Bill B.]

Re: Fuelie 461X Iron Heads #1

I used to run 461X's with a Duntov cam and dual 4's on the '57 with a 4 speed, 3.70 and Atlas Bucron Cheater Slicks. I sure miss those days!

Steven - I'll bet it was a screamer......Do you remember what was your fastest time? .....and I don't mean the solenski twins...ha ha ha!!!

Yes, Steve, the good old days!!!
Bill

[Duke W.]

Re: Fuelie 461X Iron Heads #1

I've seen that page before, but it appears a lot has been added since I last saw it. Boy, there is a lot to choose from!

Recent test data I've seen indicates that massaged 461X, 461, and 462 heads will flow in the same general range (regardless of valve size) with proper preparation - 220-235 CFM on the inlet side and 170-190 on the exhaust side at 0.5" valve lift, 28" H20 depression.

This will support about 350-375 honest gross horsepower at 6500-7000 on a vintage 327 with OE cast iron manifolds. More flow will support more power, but the peak goes beyond the above range, which may not be useable on a road engine, and 325-340 honest NET horsepower at the flywheel with close to 300 at the rear wheels with decent low end torque using the LT-1 cam makes for pretty spirited performance in a 3200 pound sports car without busting your butt at the gas pump.

As I said in a nearby thread, I've seen recent test data on some seriously massaged straight plug, 23 degree, 215cc Iron Eagles that showed around 300 CFM at 0.5-0.6" lift, 28" H2O depression. On a racing engine with headers, open exhaust, a good inlet manifold with a 750 CFM carb, and properly selected valve timing, which is too aggressive for a road engine, this amount of flow will make in the range of 500 gross HP at 7500 to 8000 with a torque peak of 4500-5000, so it's not at all peaky (for a racing engine).

On a properly massaged set of sixties vintage heads, the power is limited by OE inlet manifold flow. A LT-1 manifold will increase peak SAE corrected RWHP to over 300, but the manifold is not original and there are hood clearance problems on OE 327 hoods. With Rochester FI peak SAE corrected RWHP would probaby exceed 300.

Nevertheless, nearly 300 RWHP and 7200 useable revs with the "327 LT-1" configuration using all OE major external 327 SHP components is nothing to sneeze at.

Duke

[Stuart F.]

Re: Fuelie 461X Iron Heads #1

Have asked this question before and got different opinions; does my 63 L-76 have the 461-x heads? Short of performing it's first tear down, I can only trust and believe in a majority opinion. Several very knowledgible sources have advised both yes and no in answer to the question. What is the opinion of the day?

Stu Fox

[Timothy B.]

Re: Fuelie 461X Iron Heads #1

Stu, Yes, your car has the 461X heads. To double check, look at the casting around the lower bolt holes for the valve covers (by the exhaust manifolds) and the cast will be straight across not rounded like the other regular 461 and later heads.

That's the tell tale I always look for..

[Stuart F.]

Re: Fuelie 461X Iron Heads #1

Thanks Tim. You are so right, and I now recall that feature. Believe we went through this before, but guess today is one of my brain fade days. When I saw the thread, the old doubt re-surfaced. I haven't been able to get out to the garage much for the past few months, say nothing about seat time in the Vette. Was a shame to waist so much good weather, but believe we have a handle on things now.

Thanks again.

Stu Fox

[Steven B.]

Re: Fuelie 461X Iron Heads #1

Steven - I'll bet it was a screamer......Do you remember what was your fastest time? .....and I don't mean the solenski twins...ha ha ha!!!

Yes, Steve, the good old days!!!
Bill

Bill, I don't remember the official times (no time slips left) but I do remember another '57 that would clean my clock. 'Later found out it was a 327, .060 over, dual AFB's, and if I remember right a 375 FI cam with 4.56's. I had many street "events" and always did well based upon the '57 having no weight. One of my biggest grins was beating a 427 Ford but I believe his gears were in the low 3.00's and street tires. Later I began autocrossing the '57. Steered with the rear tires and accelerator. I did pretty well with a few dozen class trophies (usually no one else in class).

I do miss taking it out for a few runs and listening to that engine wind, especially when I pulled those round mufflers off. I guess that is what it is really all about. 'Never was a record holder but had mucho fun.

[Bill B.]

Re: Fuelie 461X Iron Heads #1

Duke - I agree, with your comments using the 327 the best choice for power as I'm convinced. But I'm using his little brother 283 .030 over that makes it a 289 and lowering my compression ratio from 11 to 1 to 10.5 to 1 flat top pistons. I need to keep the compression high do to the lower CID. Of course will be using 461X 194 int 1.5 exh using a higher lift camshaft. I selected dual pattern version giving more lift & duration on the exhaust side because of the original exhaust manifold restrictions.

Crowers 00242 462int/470exh lift @ .050 duration 220/226 Advertised duration 280/286 overlap 59 (that is 8 degrees less overlap then the solid Duntov cam), LSA 112 & LIC 108 this cam will produce 285php @ 5500 RPM, 347.9pt @ 3000 RPM I would like to try the smoother ideling cams LT-1 but believe they take a little to much of the nostalgic idle away. I'm willing to make a slight trade off in idle quality besides a 4.11 posi with a close ratio 4 speed should be just right for this application. I would really like to run the solid lifter cam but hate to be removing the valve covers once a month to adjust. The new Comp cam hydraulic lifters have a check valve that mimics the solid lifter sound as it restricts over oiling at higher RPM. I'm still experimenting and haven't made up my mind with anything as of this time. Of course I value your comments immensely.

Bill

1961 Black/Silver/Red Int. 283/315 FI
power windows. Frame off 65% completed.
1989 hard top daily driver 165,000 miles

[Joe C.]

Re: Fuelie 461X Iron Heads #1

Duke - I see it as the 461X heads beat the Dart Iron Eagle 215 massaged with equal size valves hands down....Unless your talking about a newer set of heads that didn't make Stan Weiss' 383 page flow test chart.

Check it out links below, and please give me your comments.

http://users.erols.com/srweiss/tablehdc.htm

I appreciate it,
Bill

1961 Black/Silver/Red Int. 283/315 FI
power windows. Frame off 65% completed.
1989 hard top daily driver 165,000 miles

Bill,

Thanks for steering me back to that chart. I have an older version, and this latest one contains a lot of missing information, most importantly, their "take" on the 461/462 heads with 2.02/1.6, both ported and non ported.

There is a question that I have concerning their flow numbers on the "C/ED ported 461x heads" by Meaux. Meaux is one of the fellows that I spoke to about porting my 461's, as well as Brezizinski and others. NOBODY, and I mean NOBODY promised that I would flow anything more than about 245/195 @ 28 inches water column and .5" valve lift! I do not know what C/ED stands for (computer enhanced design?), but short of major modifications including cast iron welding and/or brazing to relocate the pushrod centerlines, and angle milling to develop an 18 degree (or less) valve angle, I cannot understand how they arrived at the flow numbers for those 461x heads with large 2.05/1.6 valves installed. If anything, the exhaust numbers should correlate with standard 461 heads since they are using identical exhaust valve diameters and ports.

The only difference between the 461 heads and the 461x heads, was that the 461's had 162cc intake ports and the x heads had 172cc ports. Exhaust side was identical.

There is one fellow who posts here, who obtained probably the highest flow numbers possible out of a set of 462 heads, which maxed out at 239/190 @ .5 lift and 28 in/wc.