Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by wlewis, Nov 5, 2010.
What are the differences between a HiPo 289 and a Boss 302 engine?
The Boss 302 Mustang was a Ford Mustang high performance variant produced in 1969 and 1970. It was produced for the Trans Am racing series, while the Mustang Boss 429 which was produced the same years was built around a larger engine.
Boss 302 Mustang - Wikipedia, the free encyclopedia
I guess I didn't state my question too well. I'm quite familair with the Boss cars. I'm trying to determine the differences between the 289 HiPo engine and the Boss 302 engine.
Off the top of my head.....
The 289 HiPo (also called the "K-code") differed from the standard 289 in that it had a 'hotter' camshaft; solid lifters; smaller cumbustion chambers (which, if I remember, gave it 10-1/2 to 1 compression); HiPo exhaust manifolds (like cast-iron "shorty headers"); a 595 (not a 600) CFM Holley carb with manual choke; dual-point distributor; and other stuff I'm pretty sure, but I forget.
The Boss 302 obviously displaced 13 cubic inches more than the 289 HiPo; but it also had a 4-bolt-main-bearing-cap block with thicker block deck and cylinder walls, and a higher content of nickle in the metal It also had a forged crank and forged rods. I think it had the dual-point distrbutor and a bit larger Holley than the 289 HiPo, but I may be wrong.
The biggest change was that the Boss 302 used cylinder heads with canted rather than inline valves - what most everybody calls "Cleveland heads" because they were pretty much the same heads used on 351 Cleveland engines. They "breathe" better; so more air/fuel in and more HP out.
If I forgot anything, or screwed up somehow, somebody please correct me.
Thanks for the info.
as for performance, and from personal experience with both, the Boss 302 was way the heck quicker and faster than a 289 hi po.
The Hi-Po/K-code carb is an Autolite 4100 unit with mechanical choke, and it flows 600 cfm. Ford used the Autolite 4100 carb on other models (it came in various sizes) but the K-code is the only one with a mechanical choke.
Regarding the heads, the K-code heads had threaded rocker arm studs whereas the ordinary heads had pressed in studs.
K-codes also had a wider timing chain, 13/32 inch wide, and the balancer is wider, 1 13/16 inch versus the ordinary balancer which is 1 inch. The flywheel is different as well, and the crankshaft has an additional "hatchet" counterweight just behind the timing chain.
The distributor has dual points and condensers, as mentioned, but is also easy identifiable as it has no vacuum advance.
On Hi-Po's the fan blade has only four blades.
And the fuel pump is larger.
Another difference between standard and HI-PO 289s was a windage tray to help prevent oil foaming at higher RPMs.
Hello everyone new poster just signed up today. I built a 66 GT350 Tribute convt. The engine is a modern day Boss 302 . I used 289 block bored and stroked to a 340. Everything imaginable done to the block and crank, high pressure and flow oil Smelling oil pump, windage tray, Cobra T-Pan, Cleveland Aussie heads, aluminum dual plane intake from B&A Ford Performance . Holley 750 double pumper. It kick ass.