I’ve got a stock 5.0 HO roller cam. I know the LSA is a little bit wide on this thing, compared to the 108 or 110 LSA most ‘carb’ grinds prefer.
What will it do on a carb converted '89 5.0 HO? Just a normal Edelbrock Performer manifold, and some Tri-Y headers. Any weird issues I should be aware of? Looking to mostly drive on interstate highways, but good manners and performance are welcome, so long as it’s not at the expense of economy. With my C4 and 2.80 rear gears, I’ll need low end grunt to get my '67 XR7 moving, too.
Would it be worth it to have a custom cam ground, or will this thing behave just fine?
Don’t have any personal experience, but there’s been plenty of EFI to carb swaps done on fox body Mustangs. I doubt you’ll have any issues with the stock cam.
On the contrary, stock grinds with carburetors are no different than camshafts for fuel injection. The wider the LSA the more docile the camshaft. With a C4 and 2.80 gears you will like a camshaft with 114 LSA and .500" lift. The camshaft, torque converter, and rear axle ratio all need to be matched to one another. A stock '89 (or any other year) 5.0 camshaft is really mild so it ought to be fine.
I drove and raced that combination in the form of a '85 GT for a long time. That cam first came on the carbureted '85GT manual transmission cars…from memory, it was 202 duration at .050 both intake and exhaust, and 115 LSA. It certainly was a low and midrange combination.
It came with an aluminum version of the old low-rise 4-barrel intake that looked an awful lot like the iron one on my '68 302. When I switched to a Weiand Stealth (pn 8020), it still ran with great flexibility all over the tach…and, it came with 2.73 rear gears and a (hope you’re sitting down) 0.68:1 fifth gear! The C4 should make it snappier, I’d imagine.
Yes, it’s the 89 5.0 HO; .278/.278 with .444 lift using 1.6 rockers. 115 lobe separation.
To be fair, there was a some variation even on the “HO” cam; a degree or two here and there, etc. after it was introduced in the mid 80s. But the Cobra, and “5.0” cams (the ones used in all non HO cars) were significantly different. The HO cams are functionally pretty similar. I’m not sure if they were called “HO” motors, but the late 90s/early 2000s Explorer cams are way different too, with a much milder grind made for low end grunt. You can’t run an HO cam with one of those engines unless you put in some stiffer valve springs; the stockers just won’t handle the RPMs.
The most interesting thing to me is the more aggressive ramp rate on the Cobra cam, despite being made for 1.7 rockers.
