Hi-Po
- Thread starter hipobuzz
- Start date
You can upgrade a std 289 to the same HP levels as the original 289 Hi-po, but it won't be as durable an engine as the Hi-po was. The main differences that set the Hi-po apart were the extra care in crank selection, beefier rods and bolts,Thicker main caps, the heads had cast in spring pockets to keep the springs in their places at high rpms, and a solid lifter camshaft to let it rev higher. Plus the heads had screw in studs where the std heads had pressed in studs, so the studs on the Hi-po wouldn't pull out of the head with a hotter cam. Otherwise the Hi-po heads and intake were the same as the std 289's had as far as ports, valves and chambers.
jtfairlane
New Member
- Mar 5, 2006
- 468
- 3
- 0
In addition to what D.Hearne said, which is all correct, the 289 hi-po motors had Autolite 4100 carburetors with 1.12 venturi's and manual chokes, unlike the 2bbl and standard 4bbl 289s which had exhaust heated automatic chokes and 1.08 venturis. The 289 hipo also had high performance iron exhaust manifolds, which looked somewhat cosmetically similar to 351w exhaust manifolds.
If you are trying to make a GT350 clone, than it is important to note that Shelby did a couple minor mods to the High Performance 289 to up its advertised horsepower rating from 271hp to 306hp for the GT350. These changes included Tri-Y headers instead of the iron exhaust manifolds, an aluminum high rise Cobra intake manifold in place of the iron 4bbl intake, and a Holley carburetor in place of the Autolite. Otherwise, the engines were pretty much the same.
If you are trying to make a GT350 clone, than it is important to note that Shelby did a couple minor mods to the High Performance 289 to up its advertised horsepower rating from 271hp to 306hp for the GT350. These changes included Tri-Y headers instead of the iron exhaust manifolds, an aluminum high rise Cobra intake manifold in place of the iron 4bbl intake, and a Holley carburetor in place of the Autolite. Otherwise, the engines were pretty much the same.
jtfairlane
New Member
- Mar 5, 2006
- 468
- 3
- 0
Are you going for a totally accurate "recreation" or just want it to look right cosmetically?
If you just don't want 99% of people to be able to tell that it isn't real, you can use standard 289 heads and not have to worry about forking over close to a grand for genuine k-code hipo heads that probably need a lot of machine work and refreshening any way. The budget thing to do would be to have the standard 289 heads taken to a machine shop, press in studs removed and stud boss milled slightly to ensure you can achieve proper valvetrain geometry and machined for screw in studs. No one would be able to tell underneath your valve covers that you didn't have cast in valve spring pockets, etc. A few guys would be able to tell they weren't real hipo heads from the cast numbers at the end of the end by the valve cover rail, but they would be 1% of the field at any given car show.
Mechanically, if you want your engine up to snuff, you can find 289 hipo main caps or mexican block main caps, both of which are essentially the same, and have a machine shop match them to your block. Dual point distributors without vacuum advance can still be found at auction sites for under a couple hundred dollars. Most of the accurate and rare hipo parts can also be found the same way, like the crank counterweight, etc. but expect to pay real money for them.
A lot of things are available as reproductions, which include everything from the cam (Comp Cams makes a cam with exactly identical specs to the C3OZ-6250-C solid lifter hipo cam) to valve covers, headers, etc. You'll just have to decide what "has" to be original and what "has" to be reproduction for your own personal satisfaction.
If you just don't want 99% of people to be able to tell that it isn't real, you can use standard 289 heads and not have to worry about forking over close to a grand for genuine k-code hipo heads that probably need a lot of machine work and refreshening any way. The budget thing to do would be to have the standard 289 heads taken to a machine shop, press in studs removed and stud boss milled slightly to ensure you can achieve proper valvetrain geometry and machined for screw in studs. No one would be able to tell underneath your valve covers that you didn't have cast in valve spring pockets, etc. A few guys would be able to tell they weren't real hipo heads from the cast numbers at the end of the end by the valve cover rail, but they would be 1% of the field at any given car show.
Mechanically, if you want your engine up to snuff, you can find 289 hipo main caps or mexican block main caps, both of which are essentially the same, and have a machine shop match them to your block. Dual point distributors without vacuum advance can still be found at auction sites for under a couple hundred dollars. Most of the accurate and rare hipo parts can also be found the same way, like the crank counterweight, etc. but expect to pay real money for them.
A lot of things are available as reproductions, which include everything from the cam (Comp Cams makes a cam with exactly identical specs to the C3OZ-6250-C solid lifter hipo cam) to valve covers, headers, etc. You'll just have to decide what "has" to be original and what "has" to be reproduction for your own personal satisfaction.
The big tip-off to clone status is always going to be the Shelby American serial number tag on the driver's side inner fender. Shelby riveted these in place over the stock VIN stamping. That's the first place any Mustang hobbyist looks to sort the really good clones from the gennies. Since that's such an easy-to-spot giveaway, I wouldn't worry about having screw-in studs and hi-po spring pockets under the valve covers, or hi-po main bearing caps in the bottom end. The absence of a hi-po balancer is also something most people wouldn't notice.
I do think at a minimum that you must use a solid lifter cam, because the sound is so distinctive. The K code cam is far from radical, so any mild solid lifter cam will fill the bill. Also at a minimum, you must use correct-appearing tri-y headers and side pipes, the aluminum Shelby intake, and a correct-appearing Holley carb.
If it's a '65 you're doing, you must also install the override traction bars. That requires cutting holes in the floor pan and welding the mounts inside the passenger compartment.
I do think at a minimum that you must use a solid lifter cam, because the sound is so distinctive. The K code cam is far from radical, so any mild solid lifter cam will fill the bill. Also at a minimum, you must use correct-appearing tri-y headers and side pipes, the aluminum Shelby intake, and a correct-appearing Holley carb.
If it's a '65 you're doing, you must also install the override traction bars. That requires cutting holes in the floor pan and welding the mounts inside the passenger compartment.
Thanks guys, I appreciate the advice. My plan is to build a '66 fastback, white with blue stripes, ten-spokes, under-ride traction bars, rear exhaust, GT350 side stripes. Think I'll skip the front suspension mods but do the engine compartment bracing. As far as the engine goes: solid lifters and cam, tri-Y headers (or something close), Edelbrock manifold, 4 bbl Holley, HD main caps and harmonic balancer, aluminum valve covers. So far I haven't found a plexi rear quarter window. Any ideas?
I have no plans to try and fool Mustang guys and I plan to drive it-- not for show. Just want to re-live the 60's a little. I was there, but for some reason don't remember all that much.
Buzz
I have no plans to try and fool Mustang guys and I plan to drive it-- not for show. Just want to re-live the 60's a little. I was there, but for some reason don't remember all that much.
Buzz
