How much horsepower can cylinder heads add?

Head porting is probably the single most critical piece of adding HP. you can gain 20-30 from a really good port job.

What’s the difference between Chevy 461 double hump cylinder heads?

Also note how the spark plug on the aluminum head is closer to the center of the chamber and nearer to the exhaust valve, which improves the flame front across the cylinder. These heads have 2.02″ intake and 1.60″ exhaust valves, whereas most 461 heads came with a 1.94″ intake and 1.50″ exhaust valve.

How many double hump valves does a 66 327 have?

I concur…I have a ’66 327 (275hp) with 461 ‘double hump’ heads, and they have 1.94 intake valves. Yours could have been modified, of course, so the only way to know for sure is to remove a head and look/measure.

When did Chevy small block cylinder heads come out?

Always research a head by its casting number and date code. From the 1955 to 1959 model years, small-block cylinder heads had a different staggered valve cover flange bolt pattern. The top two bolt holes were closer together than the lower bolt holes. Valve covers were made with bolt holes to match.

What was the first Corvette double hump called?

These are often referred to as the ‘fuelie head’. These debuted on the ‘61 Corvette with the Rochester fuel injection, so that’s why they’re called ‘fuelie heads’. This is the first iteration of GM’s double hump cylinder heads. There are many different versions of those.

What are the flow numbers for GM 461 camel hump heads?

I was wanting to know if anybody knows the flow numbers for gm 461 camel hump heads with 1.94/1.50 valves? I don’t have anything for the 461 but a 186 is about 185/135. the 186 does have a better chamber and probabily a 202 valve the chart doesn’t say sorry for not explaining a little better.

What kind of head does a Chevy double hump use?

We have a good supply of used ‘186 & ‘492 heads available with everything from “Undercover Porting” to CNC Sportsman Porting. Stock “double hump” heads flow 202 cfm intake and 141 cfm on the exhaust. If you must maintain a stock looking port, consider our “Undercover Porting”.

What kind of head does a Chevy small block use?

A classic example is the GM Performance Parts 492 (casting number) stock replacement head for the early 64-cc iron heads. We included this head in our test data, and it flowed well. Out of the box, GM must have realized how bad the stock exhaust port was and added a 1.60-inch exhaust valve to help the exhaust flow.

How many casting numbers are there for camel hump?

There are at least six different casting numbers that are identified under the camel hump casting identifier. It pays to be as informed as possible, and use as much information that is available when positively identifying cylinder heads.