Can you fill the holes in the middle two exhaust? I read of some holes you can fill to gain 10 cfm? If those are not them, which ones?

 

Filling what holes in what?

 

Exhaust cross-over passages.

I've never heard of it except in all-out race heads, nor would I believe it would help that much for a street car.

 

And it would be a lot of work to do properly. I wouldn't trust any kind of epoxy filler in a head.

 

Spend the time filling in the voids under the rocker studs.

 

Precisely what I needed to know. nice place here! I am going to try that.

What kind of compression difference is there between installing 1.94/1.6 valves versus stock 1.84/1.5? I was wondering if the compression lost from unshrouding the valves was worth the bigger valves??? I would like between a 12-1 to 14-1 cr. I plan on shaving .040 or whatever the max turns out.

circletrack claimer motor. 2 bbl, ported stock intake, shorty headers

 

Exactly.

I use JB Weld myself. Never had a problem with any of the ones that I have done.

I put 1.94/1.60 valves in my 601s. Keep in mind that the 601s have a smaller chamber than typical 305 castings, since they are 267 heads. They start out around 52-53cc.

 

I always have thought they were all 58 cc until recently. So I guess unshrouding bigger valves would add around 6 ccs? Then maybe shave the max.

How much typically can you shave off after the bigger valves? How can I figure out how much I can
shave?

 

You can "cheat" a little and have the machinist set the valves a little shallow. That moves them down in the chamber and recovers some of the increased volume from unshrouding. You'll have to adjust the other other end (at the spring pocket) to maintain spring installed height or order +.100 valves to maintain spring and rocker geometry.

Setting stock Buick or SBF 351C or even some older 11/32" BBC valves in a SBC head is an option. They are different sizes and slightly longer. You don't necessarily need to jump right to 1.94" intakes, or stop at that point.

 

Did you read the GIGANTIC thread on porting 305 heads? You might find some useful info in there, since it's actually on 601 heads.

FAST355 - you use JBWeld? Don't you need a fair bit to fill in that pocket? Like i'm picturing you puddling up JBweld... Does a deep pocket of epoxy work like that? (JBweld is a type of epoxy right? Wouldn't this require a few tubes?)

I personally used this weird metal epoxy stuff. Looks like a black, short hotdog. Black center, dark gray outer sheith, you slice off a piece, play with it in your hands to mix it, then knead it into place. I hope it's still in place now

 

I have always used JB weld on carbs. Just decided to use it on the head ports one day. It stands up to fuel and to a fair amount of heat once it cures.

It is a two part epoxy.

Yes it takes several tubes of it to do both heads. But it eliminates the turbulence caused by the recession there and boosts flow. I saw 8 cfm consisitantly from my 601s.

 

Epoxy on intake tracts only. Exhaust heat is too high for it.

 

You can block off the exhaust passages in the head using melted down cast aluminum. (Old cast pistons). Block off the port hole wth a shapped piece of sheet metal as in the picture. Stick an old valve stem in the valve guide so no molten aluminum gets in the guide. Heat up the aluminum with a oxyaceteleyne torch. Prop the head up and pour quickly.
Do one side at a time. I used a cast iron pipe reduction fitting. and end plug piece from the plumbing dept as a heating bowl.

 

cast plumbing pipe fitting and plug

 

Alright. I found the holes under the studs. Whats the easiest way to apply the AB? Finger? And Im going to copy this info and bring it to the garage. I had a vision about melting aluminum down to cover those mentioned holes.

This is for a claimer motor. Might only see 50 miles before I let it go for $750. The heads are cracked already. So this is a good experiment. Thank you all.

 

Why are you using cracked heads then? Those heads are dime a dozen, why not grab a fresh pair?

If you can reach with your finger, give'r a shot. Maybe use latex gloves or something though. An old popsicle stick worked for me (during the spring when I was doing this, I went through popsicles pretty fast )

 

They are not cracked too bad. They hold 50-60 lbs.

I am using these heads to send a message. Anyone ever deal with a claimer class? I am a claim target. I expect to lose 2-3 engines next year, and this one will definately be gone after the first race.

So if anyone has any cracked 601s or cracked 2 bolt blocks Im interested!

 

Ok, just looked up claimer racing. That's weird.
Anyone can "claim" a car, and buy it for $400 or something? But then it must be raced in the next race. So you're a claim target, ie, people usually want to buy your car, because it's a winner?
So you expect someone to buy it, and ideally it'll fall apart during their next race? Then you....? Somehow get another car and engine real fast?

 

Well kinda. I race a Limited Sportsman/Superstock type class on a 3/8 mi pavement oval track. This class has no engine rules whatsoever. But they have a claim like IMCA. http://imca.com/rules.php?divisionid=10

Basically If I guy wants your motor he can have it for $750 OR you can swap engines with him. If you refuse its a $1500 or a 1 yr suspension.

This track I race at is in another country and I have won the championship the last two years. They dont like Americans winning I have found. Sad but true. I used to think racers were racers it doesnt matter where you are from, but. I am getting ready to get claimed 2-3 times next season and Im letting it be known what I am using. helicoiled blocks, cracked 2 bolts, etc. I do plan on having stuff last though.

I did some thinking about melting down the aluminum. Doesnt aluminum melt at around 1200 deg F? I have melted down lead in the past, and that goes at 400. Thats too hot. Too much hassle???

 

So... you're in like michigan, racing in Ontario? I can see that, just because Americans get the parts a lot cheaper, so you can build a $750 motor for you, but other buddy has to pay $1200 for the exact same thing. Kinda makes some bitter, I would guess.

haha, sounds like a cool racing circuit. You can keep the car, that's nice - only the motor is up for grabs. I would be all over this type of racing I think.

I think using AL to fill the exhaust crossover is too much hassel. You might be able to grind some chunk of steel plate to roughly fit over there, then braze/weld it in place, and grind it smooth. I still wouldn't bother though.

 

Back when I was building motors like that, I AVOIDED the motor claimer classes like the plague. There was NO WAY I could build a motor at under a $500 (or whatever) claim for a class that paid like $200 to win, that would stay together. Most people in that type of class would just get a junkyard hookup and put in a "new" junk short block every weekend or 2.

I DID do some work for people that ran in a CARB claimer class; the rule was a 4412 carb with a $250 claim (you can kind of tell how long ago that was...).

Some of the other classes I can recall were the cam "lift rule" class (had to be .390"/.410", but you could make it have ANY duration you thought you could get away with); the 1.25" valve spring class (any cam you wanted, but the VSs had to be 1.25", kind of hard to go too wild without breaking stuff which pretty much ends your night), the F70-14 right rear tire class (that was at a dirt track, the motor kind of fades to zero importance when the guy that wins is whoever gets that to hook to the track the best), and a few others like that.

But yeah if you win, or even if your car runs harder down the straight than somebody else's, they'll claim it for sure. It's always a good defense to make sure that if they do they get GARBAGE that they can't use. Word gets around QUICK that claiming your stuff is a waste of time, except for creating a hassle for you.

I bet block filler would work... put duct tape or some such over the crossover hole in the port, and pour it in from the intake side....

 

I know mailorder costs a lot more up there, which is a big part of anything now. My car parts are 90% mailorder. Tires seem to cost alot more too.


Is there alot of resentment/tension in southern Canada for Americans? We (3 cars) have been racing there for 5 years and we are still "The Americans".

Thanks for the help on the heads. Im starting my second set of 601s today. Im not sure if I am going to leave the stock valves in and shave them .020-.040 or go with the larger valves. I would like the higher cr, but not sure if I want to buy my fuel in drums.

The first set I installed 1.94/1.6 but had to open the head up to 62cc to do it (first time). I unshrouded 3/16"s around the intake valve.

 

Not even a bit. I can only speak for western canada though, Calgary and Alberta. We're a bit different from the Eastern guys though. Little more right wing, pro-USA, pro-industry, anti-Kyoto etc. Compared to the people in BC or Ontario (more anti-bush, left wing, etc.)
I don't want to spark a political debate though...

Do you backcut or radius your valves yourself? I started a thread on here with some pictures of how to...

 

i radiused and backcut myself down at the local Carquest. Any pictures of that would be appreciated. The set I started on today turned out to be 416s for my 355. I think I am going to leave the stock valves in there and unshroud them about 3/16ths then shave about .040. Does that sound right?

 

boy, this was hard to find...
https://www.thirdgen.org/forums/tech...ighlight=valve <--- not terribly useful I don't think

https://www.thirdgen.org/forums/tech...ighlight=valve
I think my picture links are dead right now. Lemme see if I can fix that...
.
.
ok, they should all work now. If you look at the file "link", it's picture 6 in the director. If you delete the 6.jpg, you can view the directory. Files 1-5 are other pages from that book, scanned in. Basically vizard explaining what mods gave what results.