Those numbers relate to the ratio, pushrod size is generally a diameter callout along with a length dimension. As with any part, the intended use and/or combination of components will dictate the ratio, oem rocker ratio is 1.5 for sbc, for a purely street car there's no need for anything else, besides the mfg suggestion, many engine builders may choose ratios, sometimes intake only, sometimes exhaust only, sometimes both.
Since both of my engines have guide plates it helps eliminate most sideways pressure. The full roller rockers are very expensive, but stamped steel roller tip rockers are very reasonably priced, and not that much more than stock type quality stamped non roller tip rockers. For the small extra of roller tips I'm happy to pay the price. I'm not a fan of full rollers just because of the extra needle bearings that I think add to another place they might fail. Plus the stamped roller tip rockers fit under stock valve covers, which is a nice bonus.
I appreciate all the information on here guys. I really enjoying learning as I work through this build. When I get the heads back I will post a quick picture of them.
Yes, that's why I like roller tip rockers as they don't drag across the top of the valve stem. Less friction, less wear, and a slight HP gain.
Super Stock heads must check at factory port and chamber volumes for the engine/horsepower claimed. It takes hours and hours of welding and epoxy work to build a compe***ive set of heads that will check legal. Very different thing than what is being discussed here.
Speedway double humps vs oe. I had to grind slightly in the exhaust manifolds to clear the valve cover. It's back up and running which was the goal and looks close enough to how I started
Speedway double humps vs oe. I had to grind slightly in the exhaust manifolds to clear the valve cover. It's back up and running which was the goal and looks close enough to how I started. I never knew they made a replica style head to the OE Camel hump. Would you happen to have a picture of your alternator side set up since these do not have any holes drilled? Might want to add these to my SBC 283 one day.
No good pics. It is 66, ,67 Chevy truck manifolds and brackets 1967 manifold in my case. Mounts to the front of the manifold, not the side, with a bracket that bolts to the manifold and water pump for the bottom bolt
No good pics. It is 66, ,67 Chevy truck manifolds and brackets 1967 manifold in my case. Mounts to the front of the manifold, not the side, with a bracket that bolts to the manifold and water pump for the bottom bolt View attachment 6317231 [/QUOTE] I see that, thanks for the details on the manifolds and bracket.
i still run a set of pro top line alloy sbc heads they were bought out by rhs but i am pretty sure still made in Australia or new Zeeland
here are a couple of pictures of my alternator setup in my '40. It uses a stock Chevy mount and adjustment strap. I welded a part onto the drivers side header ( which I built). These 2 pieces can be used with manifolds or headers , but do not move the alt. up enough to clear the valve cover. They were used a lot in the '60s and maybe '70s. They are not very elegant but could be modified pretty easily.
Did you make the 60's style as well? I like those. With my SBC283 the valve covers do hit the back of my alternator. The cast iron heads that are in the machine shop are a set off a 66" 289 block with the slotted push rod holes.
He is using the same Chevy truck lower bracket as I have, with a homemade bracket to support the back with headers. Very nice. I will copy this when I put my headers on, as it provides superior support over the side mount header Mr Gasket bracket
Been a long time coming but I finally got my heads back today from the machine shop. Exhaust valves were machined a tad bigger than stock. Just need some rockers now and a ARP bolt set. https://arp-bolts.com/kits/make.php?_Make=400&_EngModelID=579
289 stroked, here is the thread...https://www.jalopyjournal.com/forum/threads/stroking-289-budget-build.1311237/
Howard Johanson was selling them, cast aluminum SBC heads, in 1957. Howard was always ahead of the curve. I would not be surprised if he didn’t start on them in 1955. In 1955 he already had a 352” SBC. 1/8” bore and 1/2” stroke!
I’m too cheap to buy new one. As long as my local one man gang is operational, I’ll use old heads. Last set was power pack heads. New guides, worked the valves, cleaned em $200 Had some 2 humps built with hard exhaust seats. Think I had 350 in the set with guides, seats, springs and valve job but I also could give 2 rips less about going fast
Hate to say it, but $2500 wont buy you much of a set of heads. Stocker heads, when done the way they need to be done to perform, usually involves going thru dozens of heads, checking flow and volumes, lots of painstaking and time consuming work,, and parts are getting hard to find for many engine combo's these days. Depending on the combo, certain aftermarket NHRA approved heads are now legal replacements for some combos, such as square port 60's big blocks.
Yep, as they allow more after market heads & components the stock, super stock has gotten out of reach. Maybe IHRA can reverse that, make them run stock iron, safety fan, alternators. I really like the muscle car drag stock approach. I have a 69 Camaro that might have ex manifolds soon.
Now if I was going out to compete with a 358 or a Big Block D.I.R.T modified (Aluminum heads are legal) by all means I would run them, I would be foolish not to! However that is not what the H.A.M.B. or period correct, or true vintage racing is all about. It is about respecting, honoring and replicating the past. So no to build a true period correct car, other than a Ford flathead, or a later 1960 modified stock car with L-88 heads as they did in period (some even ran the ZL-1 aluminum Big Block, however the chances of finding either of those is nil!) I have no interest in aluminum heads
Yep,, NHRA has been allowing (accepting aftermarket items that benefit vendor,sponsors business markets) that have gotten really nuts IMO. Lets look at after market disc brakes for example,, if they make it available, EVERYONE is gonna have to change to realize the performance advantages the compe***ion enjoys with the product. Why would a fairly slow and low dollar Q,T,R,U car need to spend thousands of dollars to stop? It has to do with reduced weight in areas that you have to mimic if your playing the NHRA game, the examples are many over the past years, making it a rich mans game. Currently building a very low budget but NHRA legal 61 Bel Air,, no fancy body work or paint, car is solid underneath, I've done all the rear axle mods and bracing most X frame cars need, doing it as right as I can, but mimicking the 60's standards, just hoping to have a fun car, not a financial disaster. Appears more and more folks building old time stockers, super stockers, g***ers, as well as FED and searching out Nostalgia events, like the Melt Down drags in Byron, an example of a fun race with sane money spent, just looking for fun. Not bashing the NHRA racers, but the fun days seem to have evolved away over the last 20 years or so. At least for me and others I know that have drifted away, it's fun building a car like I have now, really excited as it comes together. Many thanks to my friend, Scott Chalk, who presented this 61 Chevy situation to me,, a good friend indeed.
The Jalopy Journal
