Here's the deal. I have a stock 440 out of a 76 chrysler new yorker with 80,000 original miles on it. It is going in my 73 challenger with a 727. Due to budget concerns and the fact that it runs fine now, I don't want to dig into the bottom end right now. I also have a spare set of identical stock heads to play with. Does anyone know if and how much you could deck the heads to increase compression? If so, how much would this increase my ratio? I think a cam swap is a given so any ideas on what kind of cam would work good with my combo? What about porting and polishing the heads? Is it worth doing? Could I do it myself? Or would the mopar performance Stage V heads still be a better deal? Any advice on intake manifolds too? Thanks for the help, I don't know too many people who have much experience with mopars, so any advice/personal experience would be greatly appreciated.
Ryan
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by HemiRick » 20 Dec 2004 16:17
The problem with any post 71 440 is the pistons. Too low a compression ratio for any kind of performance cam. Milling the heads will only rasie it about 1/2 a point and ruin a set a of heads. Save your $ and don't do anything but drive it untill you can change the pistons.
- HemiRick
by dave-r » 20 Dec 2004 16:28
I agree. Without knowing what your budget actually is I would suggest you wait until you have enough money put by to swap on a set of big valve ported heads, new cam/lifters, and pistons.
Power is made by the cam and heads. They have to match. Heads that flow too much for the cam and rpm you use the engine at will hurt performance rather than improve it. Don't just throw parts together. Decide what you want from the engine and work from there.
Power is made by the cam and heads. They have to match. Heads that flow too much for the cam and rpm you use the engine at will hurt performance rather than improve it. Don't just throw parts together. Decide what you want from the engine and work from there.
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by ryanb56 » 23 Dec 2004 7:16
I guess I will hold off until I can afford a new set with new pistons. As far as the heads go, the only real head options I have seen are the edelbrock performers, the mopar performance stage V's, and modifying the stock ones.
When you say "big valve" heads, the only size I've seen is the 2.14/1.81 which is the same size valves as stock correct? What can you do to the stock ones to make them flow better? Or is it a better choice to go with aftermarket castings? Are there other aftermarket castings that I don't know about?
When you say "big valve" heads, the only size I've seen is the 2.14/1.81 which is the same size valves as stock correct? What can you do to the stock ones to make them flow better? Or is it a better choice to go with aftermarket castings? Are there other aftermarket castings that I don't know about?
- ryanb56
by dave-r » 23 Dec 2004 8:59
Christer is correct.
The thing with bigger or ported heads is you need to decide where you want to be power wise first so you only go as big as you need. Using heads that flow too much for the size engine, cam and rpm it works at will hurt performance especially at the lower end. This is because the bigger the volume of the port runner, the slower the airflow. You want to keep as high an airflow as possible but still flow enough for the engines needs. Otherwise you have poor throttle response and fuel dropping out of suspension and running down the port walls.
In other words (as I have said earlier in this thread) pick a cam and head combo that match.
Read all the stuff on the Hughes Engines website as they are quite good at explaining it and give you examples.
The thing with bigger or ported heads is you need to decide where you want to be power wise first so you only go as big as you need. Using heads that flow too much for the size engine, cam and rpm it works at will hurt performance especially at the lower end. This is because the bigger the volume of the port runner, the slower the airflow. You want to keep as high an airflow as possible but still flow enough for the engines needs. Otherwise you have poor throttle response and fuel dropping out of suspension and running down the port walls.
In other words (as I have said earlier in this thread) pick a cam and head combo that match.
Read all the stuff on the Hughes Engines website as they are quite good at explaining it and give you examples.
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dave-r - Grumpy Old Man
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by Follicly Challenged » 26 Dec 2004 21:22
If it's a stock bottom end, and you're not redo'ing it, you don't wanna be spinning it too high anyway.
Seen lots of stocker type stuff return decent street power output for what they are with a simple cam swap and head job.
Pistons .125" down hole and all ! Yes, the quench sucks, but they ain't heating enough to worry about it much anyway.
It's all what the budget dictates, but if you're gonna try, here goes,
Remember, port velocity is torque and flow is HP, but at these rpm's the head is well suited with the stock valves.
Stay to around the low 5,000's rpm, 5300 tops with better intake, add a comp 268H, rebuild the heads with a std 30/45/60 3 angle valve job, spec the 45 seat closer out to the edge of the valve and make sure the 60 width is cut down with a 70 deg or higher in the throat(4th) so it's (the 60)no more than .125" wide. Add the old "single with a damper" magnum springs installed @ 100 lbs on the seat. (any casting, 452 or 346 preferred)
Backcut the "ski ramp" off the stock intake
Use a 10/40 penns, grade oil, no shelf brand high parafins crap.
Bump it to 10 or 12 deg initial with a stock dist curve
Stock intake and Thermobog (lighten 2 secondary air valve adjustment)
You may be surprised how much it responds !
It all depends on how much you want, 'ya can't exceed the size of your wallet !
Good luck, hope this helps
Seen lots of stocker type stuff return decent street power output for what they are with a simple cam swap and head job.
Pistons .125" down hole and all ! Yes, the quench sucks, but they ain't heating enough to worry about it much anyway.
It's all what the budget dictates, but if you're gonna try, here goes,
Remember, port velocity is torque and flow is HP, but at these rpm's the head is well suited with the stock valves.
Stay to around the low 5,000's rpm, 5300 tops with better intake, add a comp 268H, rebuild the heads with a std 30/45/60 3 angle valve job, spec the 45 seat closer out to the edge of the valve and make sure the 60 width is cut down with a 70 deg or higher in the throat(4th) so it's (the 60)no more than .125" wide. Add the old "single with a damper" magnum springs installed @ 100 lbs on the seat. (any casting, 452 or 346 preferred)
Backcut the "ski ramp" off the stock intake
Use a 10/40 penns, grade oil, no shelf brand high parafins crap.
Bump it to 10 or 12 deg initial with a stock dist curve
Stock intake and Thermobog (lighten 2 secondary air valve adjustment)
You may be surprised how much it responds !
It all depends on how much you want, 'ya can't exceed the size of your wallet !
Good luck, hope this helps
- Follicly Challenged
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