I did see this on youtube a guy bought a set of aluminum heads completely assembled straight out of the box. Sprayed some cleaner in the valve guide and it leaked out of the valve. He shined his light in the guide with the valve in and saw the light around the valve. AFR was actually the first brand on my mind. I see them on motortrends engine masters all the time they seem great but havent looked at their company yet. Regardless of the head it would be taken to a machine shop to get machined and have proper seatment of the valve. Yes all he wants is a cruising pavement pounder. Hes not trying to set landspeed records lol as far as budget, i think just a shade over 2grand would be the absolute most i would spend. Certainly not 3grand thats a little much. The manifold will probably be left as is because it is a good manifold. Regardless though the heads will be sent out and machined, to save a ton of headache when they are installed. This way we can just button up the engine and go
Unless you need a brand Name engraved in your heads. Just get a set of bare castings, then you get a better choice of the valves and springs..
One part is never the answer it is all about the combination. https://www.summitracing.com/parts/tfs-k314-420-395/reviews/ If you know the combination fine but if you do not I say go with one put together by experts.
Yes, i would say i dont know 100% the combination of pistons, cam ect. This is only because i have asked him and he has said he cant remember. Found out he had the motor done around 92-93 by looking through his receipts for the car. I may just try to get a set of bare castings and let him decide on where to take the rest of the top end. As long as hes got the heads to play with a little bit
As always, the best builds are when all the components work together. Before buying heads you will need to know what pistons are in it because you will want to know what chamber size to buy. With aluminum heads on a 350 you would be fine with around 10 to 1, so you could easily go with a 64cc chamber. In my case I ran Trick Flow 195 heads with 62cc chambers. Experience has taught me that a Comp Cams XE268 is pretty hard to beat for a great performing street cam with no bad habits. It'll give a nice sounding thump on idle but will smooth out right out off idle. You already have headers and your Performer RPM intake will work great with that combo. Add a 3310 Holley and you're all set. I ran a 13.20 with this combo in a 3,800lb car with a 200-4R and 4.10 gears but it could work very well with other combinations.
Found out from him nonchalantly, that the motor is a 71 chevy 350, stock pistons, crank, rods etc. The heads are stock 193 heads. The block is punched .030 over and has a 2 bolt main, 1 7/8th headers with 3in collectors. Mild cam unsure of duration. Edelbrock 600 cfm carburetor on top of an edelbrock performer rpm intake. Tranny is 2 speed powerglide with a shift kit in it. The rear gears are factory 1965 2.73's (airplane gears) that have never been changed
This was all the information i can get from him. I believe the block was line honed as well. He did not have it zero decked. This is all could find from him if this would help
Generally speaking, we often refer to heads by the last 3 numbers of the casting number but since I know of no heads with 193 in the casting number I assume you meant that they have stock 1.94 intake valves with 1.5 exhausts, and if it is a `71 engine with it's original heads they would also have 76cc chambers. You would have a lot to gain when buying aluminum heads by going with 64cc chambers and 2.02/1.6 valves. The valve sizes would be a given because I know of no aftermarket aluminum heads that have smaller valves. The 64cc chambers will gain you some compression, which will be very helpful. With that said, you are losing a great deal of performance in the driveline. I know you are not looking to do a complete driveline swap but this would be something to consider in the future. A 200-4R transmission swap and 3.73 gears would wake the car up even more than a cylinder head swap. The combination of the 2.74 1st gear and 3.73s in the rear will give it much better performance off the line, so much so that it would surprise you. And the combination of the 3.73 gears and .067 overdrive would yield a final drive of around 2.50, so you have the best of both worlds without even touching the engine.
Yes he said that they are stock heads, he probably did mean 192 lol I talked with the guy at promaxx on my break this morning and he recommends the 185 series heads that they make. And the combustion chamber sizes that they have are 72 and 64 cc both have 2.02 intake, and 1.60 exhaust. I would go with the 64cc. Those heads with a hydr. flat tappet are good up to .575 lift on the cam. He has talked about switching the gears, hes never mentioned about the switching the trans, which is a good idea. The only thing he wants to do with the trans is put a stall converter in it. I dont know how much of a stall though. The heads do come with the straight plugs which are nice because he wont have to reconfigure the header situation too much lol
Yes, with that combo you're not going to want to go "overkill" on the heads. With a mild cam, your biggest gain is going to be from the raise in compression the new heads would afford, but something that would really help make some horsepower "since you're in there" is a cam swap. But, if you swap the cam, he's definitely going to need to gear down and a trans swap to a TH350 would be a massive help. A Powerglide 1st gear is very tall, so you actually need all the bottom end torque you can get. A cam swap for more power is going to kill the bottom end torque. If he's liking the car's characteristics the way it is, and is really wanting the heads for the cool "hey, check it out, I've got aluminum heads" thing (nothing wrong with that), get some aluminum heads designed with good port velocity, small chambers, and some decent size but not huge valves like the 2.02/1.60, and it'll be a great street engine.
He has actually talked about going to another cam, maybe slightly bigger when he pulled the engine to regasket everything. What would be defined as a good port velocity?
If he goes to a bigger cam, he will need a stall converter and most likely lower rear gears. A swap to a TH350 would alleviate those issues somewhat, because the 3 speed has a much lower 1st gear than the 2 speed Powerglide. With a Powerglide, it's almost like you are starting in 2nd gear with a normal 3 speed automatic, so you need all the bottom end torque you can get to get the car rolling. In simple terms, installing a stall converter lets you skip up in the RPM range before the car starts to move, so you can skip over the bottom end and start at a higher RPM where a big cam starts to work before putting a load on the engine. There is no set spec or figure for port velocity. In simple terms and all things being equal, a smaller port will need to flow air faster to have the same CFM as a larger port, and will have a higher flow at a lower lift. Higher port velocity and a smaller valve/port helps bottom end (to a point). Big ports and valves are for top end power, and will kill bottom end torque because the port velocity is too slow at the low RPM. Think of it like water flowing. If I've got 1,000 gallons of water I need to move 100 feet and I've got 1 minute to do so, think of how fast the water is going to have to flow through a 1" tube to get all that 1,000 gallons out. Now I've got 5" tube, the water can move at a much slower rate but still travel the same distance in the same time. The 1" tube scenario will have a much higher speed than the 5" tube. But eventually if I need to move more water, say 10,000 gallons, that 1" tube will never be able to keep up and won't be able to pass the 10,000 gallons in that minute. I'll need that 5" tube to get the job done in 1 minute. It's the same with engines. If I've got a small cubic inch engine and a low RPM ceiling, I don't need that big tube (port/valve) to flow what I need. As a matter of fact, that little port/valve works great because it keeps what I've got moving quickly. A big port/valve will just slow my fuel and air down until I get up in the RPM range or cubic inch size to necessitate that bigger port/valve. Once I get a bigger cube stroker engine or a high RPM limit, I need that big tube (port/valve) to move what I need to feed the engine. The little valve/port will begin to hold the engine back. Sorry, kind of a long drawn out analogy, but I hope it makes sense. Back to my original suggestion, I think you did the right thing calling Promaxx and I'd follow their advice on which head to get. Looks like they're sending you the right direction. Engines/transmissions/cars need to be put together as a COMPLETE combination of parts. Big ports and valves don't like heavy cars, small cams, and highway gears. The opposite is true also. EDIT: Here's some good reading I just found: http://performancetrends.com/blog/?p=315
That makes perfect sense, and the analogy too haha i told the guy at promaxx i would call them back if i got the chance tomorrow. I will ask about the smaller valves/ports
Port velocity and the things you and I were talking about are the exact reasons he's recommending the 185's . They make a lot more "radical" heads, but for your combo I'd be recommending those 185s too. If you were thinking you were going to change cams, rear gears, torque converters, etc. I might be looking at their MAXX 190s.
These would be cool on a `65 El Camino https://www.summitracing.com/search...y=Default&SortOrder=Default&autoview=SKU&ar=1
Lucas I've never thought of it quite that way or even heard it explained that way but I think that's an excellent analogy! Makes it easy to understand and comprehend for everyone. Kudos!
Double check the header size. 1-7/8" is HUGE for that build. 1-5/8" would be a better match for a cruiser. Agree a transmission swap to a 3 speed or 4 speed would help the street feel immensely! Don't bother with a hi-stall converter with the 2 speed and those gears..... it'll be revving to stall speed every time you hit the gas. That gets old fast. I liked Derek's suggestion of the low-duration/hi lift roller cam (Post #14). Retains low rpm street torque and it breaths well at hi rpm too. Mo' money tho.
