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65/66 mustang the only stang worth a damn
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Comments
Thanks
Bri66
Other than that, you have to "do the math" if you are modifying your compression ratio in any way with special pistons or milling. If you end up with too high a compression ratio, you are going to find it hard to get the proper octane fuel.
Can you briefly describe what "hardened valves" means? While I'm not a mechanic, I certainly know what intake and exhaust valves are and their purpose. Thus, hopefully you won't need to "dumb down" your reply too terribly much.
Thanks
So Stellite will prevent this from happening. Obviously, you are not going to be able to buy a lead additive for your fuel.
Is hardening the valve seats an expensive process (what kind of shop does this?) and how does one know if its needed in their particular car?
My suggestion would be to see if there are any '71-up heads that will work on the cars you like. 1971 is the year they made engines compatible with unleaded and lowered compression ratios. These heads not only have the hardened seats but (sometimes) larger chambers that give a compression ratio that tolerates 91 octane.
This isn't always an option--I don't know if '71+ Cadillac heads will bolt to a '62 390 block, for example, although they probably will--but it kills two birds with one stone.
Later heads are a straightforward swap with the GTO and Mustang you've been talking about. With the '62 Cad it gets a little complicated. You'd want a machine shop to check valve-to-piston clearance, and make sure the large chamber 472-500 heads don't give you a 6:1 compression ratio with the 390's smaller cylinders. And there'd be a port mismatch but I don't think that's a big deal.
On second thought, just yank that puny 390 and bolt in an Eldorado 500.
This article may raise more questions than it answers, but it appears to be a pretty good technical reference source.
http://www.wauknet.com/douthitt/octane.htm
He defines knocking as uncontrolled combustion *after* the spark plug fires. My understanding is that "pinging" can also come from "pre-ignition" which is uncontrolled combustion *before* the plug sparks. With pre-ignition you've got combustion pressure trying to drive the piston down as if it was on its power stroke when in fact the piston is on its way up on the compression stroke. This shortens the life of the reciprocating parts considerably.
He also talks about the advertised or nominal compression ratio usually being higher than the actual CR. Some engines came with two head gaskets--take one out and you've got a higher CR. Because of manufacturing variances, combustion chambers in the same head usually aren't all the same size. This means you can have a small chamber that starts to knock before the others do because that cylinder has the highest actual compression ratio. You can "cc" the heads to make sure the chambers are all the same size.
He also talks about "lazy" ignition timing in '70s engines, something I had also mentioned (great minds thinking alike). I wish he had talked more about how productive it can be to recurve the advance and crank in more initial advance. That has a huge effect on combustion pressure and you can use it to compensate for a compression ratio that's too low or too high.
He also talks a little about some of the other factors that influence knocking. He doesn't go into much detail so I'll try to fill in some of the blanks.
air temperature (both ambient and underhood)--the hotter the temp the more prone to knocking the engine will be. And of course it's even hotter under the hood. Most factory "ram air" packages were actually cold air packages, since the scoop was usually placed in a location with little ram effect.
head temp--how well the engine cooling system cools the combustion chamber. He also doesn't mention how cylinder head design (hemi or wedge, open or closed chamber) has a big effect on knocking.
load--lugging an engine increases its tendency to knock, but where this really shows up is in cars with freeway gears (ratios less than 3:1).
spark plugs--have different heat ranges. A colder plug lessens the tendency to knock, but a plug that's too cold will foul ("load up") with carbon and quit firing.
I also wish he had talked about water injection. Most people think this is just a gimmick but I understand they used it on WWII fighter engines.
Edelbrock made an adjustable water injection that I used in the mid '80s. It had two adjusting screws (can't remember for what now) and it worked.
To expand on this, is there an easy, sure-fire way to tell if the seats have been hardened? I'm thinking a seller could say he's had this done when he actually did not. How can you tell?
And, how much should one expect to pay for this hardening process?
Considering how cheap and fun a 289 Mustang is, I don't understand why anyone would buy a six-cylinder Mustang. They're not bad cars, but a little extra money for a 289 gets you a faster, smoother, quieter car with more appreciation potential.
The only headers I ever had were some museum pieces I found in a wrecking yard around 1971 and bolted onto a '61 Impala 348, so I'm not a leading authority on them, but I can tell you that they made a big difference open and absolutely no difference after I had the exhaust system hooked up.
-Jason
but rubbed the passenger side shock tower. Installed some Hedmen tri-ys. Too bad too. Top of the line ceramic coated Super Comps just sitting in my garage all boxed up. When I take it in for it's paint job I'll have the body shop notch out that tower and install them then.
Maybe if the engine had been more radical--more cam and carburetion--headers would have made more difference but you've still got to hook them up to an exhaust system that won't get tickets.
The hi-po 289 came with streamlined iron exhaust manifolds and I think they repro them now. That's how I'd go. At least you know they fit.
Just an aside to anyone interested out thier, you don't really need to get every available last HP potential out of your engine in this car. It's so light that if you can get close to 300 HP, be satisfied with that.
I stuck a totaly built, stroked mill under the hood (a tad over 400 HP) and aside from the ability to smoke my tires till they're bald, the car is not really able to utilize that power effectively in the real world. If I had it to do over agin I probably would've saved a few grand and stuck a 5.0 crate engine in there.
I do have a question that hopefully someone can help me with. Since the drive train on my car is done completely I am now ready to commence the bodywork and have decided to turn my pony into an all out street rod utilizing some pretty wild looking fiberglass parts from Mustangs Plus out here in California. My question is this. How do you attach fiberglass parts to sheetmetal. They sell some shelby fender flairs (1 1/2") that I am hoping will solve a problem with my front tires rubbing against the fenders. (17" Cragar SS with 8" Falcon low profile Z-rateds)
They also sell the entire fiberglass fender with these flares molded in. These cost more than twice as much however so I would prefer to use the "flares only" unless these pose problems that I am unaware of.
Also, no lectures about "destroying this car", I bought it as a 6-bangar and ripped out and replaced the engine,tranny, and rear end and also the dash (new gauge clustter w/white face gauges)and shifter. So it's "technicly destroyed" anyway.