So we purchased a 1975 mustang II Mach 1 (I know it’s not a Mav or a comet) with a hot 289, c4 trans, and narrowed built 8 inch rear end. Pulled the motor to freshen it up (leaking bad from sitting). All the ears of the 1965 289 block were either cracked or broken off. So we need to build a new motor. The build is a super low budget build because the car will need a few more things. I picked up a super low mileage short block out of a 1992 mustang 5.0 roller motor with stock forged internals. The bearings look great and I’m considering just rehoning and ringing the block and that’s it. I have a free set of explorer GT40 heads off a scrapper that I’m going to bench port, and I’m thinking about using the intake and carb setup off of the old motor, which is a Eldelbrock 289 performer intake and Edelbrock 600cfm carb. With this being my first build, I don’t know what roller cam to choose and what head gaskets to go with for potential spray down the road. Any advice would be greatly appreciated.
Welcome to the site from northeast Ohio!!! If this is a super low budget build and the 5.0L roller engine is low mileage and appears to have been well maintained, I would leave the short block as is, no honing or ring replacement. If this is your first build forget bench porting the GT 40 heads, you may do more damage than good. Spend your money on having the head surface and guides checked and a valve job performed. You might want to check spring pressures at the same time. The camshaft I'm suggesting requires a minimum of 125psi and up to .500 lift. That Edelbrock Performer intake is a low performance piece (weakest point of your build). Not much difference in that manifold from a stock intake other than weight. RPM range for that unit is approximately idle to 5,500. You should choose a lower performance super low budget camshaft to match your intake . How does $73 sound? https://www.summitracing.com/parts/sum-3601/overview/make/ford If you install a better performing intake you can then step up to a higher performing camshaft. Something to consider. As for head gaskets and keeping with the low budget build, I like these Fel-Pro pieces. Don't error and not order two. https://www.summitracing.com/parts/fel-9333pt1/overview/make/ford Just my opinion.
"a super low budget build." "a super low mileage short block" run the cam that's in it... if you change the cam the cam bearings, lifters and springs need changing also...it's a snowball effect.
I agree on short block, if it isn't worn use it as is... That said, a friend dingle balled, plus inst fresh rings & bearings in the '86 5.0 I ran in my T-bird for nine years... It finally succumb to blown head gasket(twice) from me spraying it with 150Hp shot... Damaged the block deck... If I'd stayed away from the spray that engine would likely still be running... The stock 5.0 roller cam isn't horrible, I'd run it with 1.7 rockers... If you really want to wake it up use the TFS Stage 1... TFS also sells a spring kit good for .600 lift(yes no doubt over kill for your application)... Note if you are using the unique Stang II spec C4 with 141 tooth bellhousing, I don't know of a flexplate that balances with the 5.0... There are aftermarket, 157T, 50oz available for the late engines... The larger 157T bell housing was used on most smaller and intermediate models... Was also a 168T version used in larger automotive and truck applications... If you use the 28 oz 289/early 302 flexplate you're gonna have a paint shaker...
Sorry i shouldn’t have said “super low budget”. I’ve got the block and the GT 40 heads and there is about $1000 of budget left for just the motor. If I have to upgrade rockers, valve springs, intake, and a good cam I should be fine. Just looking to get the most out of my setup N/A, was thinking it would be nice to be able to spray later down the road. But it’s not necessary.
Did your 289 have a 5 bolt bell housing? Probably does not, but I cant tell from here and wouldnt want that discovery made upon assembly.
Also, just to avoid potential grief, If your 5.0 motor came from a manual transmission car, make sure you remove the pilot bushing/bearing from the back of the crankshaft if you use an automatic. Welcome to the forum BTW!
Do you already own the tools and have the consumables needed to port your own heads? If yes.. or only needing to spend around 100 bucks or less to get set up?.. seems like a no brainer to me. Put your cash where it has the greatest impact. I also vote for a slightly bigger cam and a larger taller intake manifold.. preferably an airgap style to help cool the intake charge, allow more aggressive tuning and/or increase detonation resistance. Pretty hard to get an intake too cold when it comes to power production and detonation resistance. The idle to full throttle gains to be had from even a very mild porting job on both the intake and exhaust ports of those heads is extremely good from a $ to horsepower gain standpoint. The biggest primary gain in efficeincy and outright cylinder head power potential would come from a decent 4 or 5 angle valve job. The bowls are horribly shaped, sharp and choked up. Especially the exhaust side which will need all the help it can possibly get(could never have too much with that casting).. especially if considering a light spray later down the road. Nitrous is similar to boost in that the exhaust must deal with greater pressures and larger exiting mass compared to N/A stuff. Obviously they(5.0's can make decent power.. but if you have the time and means to improve the induction package while it's apart?.. go for it!
IMO, don't mess with the heads...easy to screw up, then you're back to square one again. Keep your $1000 leftover for fluids, filters, that kind of stuff. Then what's left over, chunk it in a jar for another engine later on down the road. If you're having any thought of nitrous use, you'll need spare parts. Reason I say don't mess with the heads is because no matter how much you put into them...work or whatever....they don't even come close to aftermarket offerings as far as value. When I say SBF iron heads suck, I mean it. I personally picked up ONE SECOND ET and 10mph going from PORTED D0OE 351w castings (which at the time were believed to be the better of the factory Ford offerings) to out of the box Edelbrock Performer RPM heads; without a single other change...aside from jetting and timing adjustments. 1 full second (1000'). 10.20's to 9.20's.
