There is an age debate which is sure to come up so I might as well do it

There are some schools of thought that say "If you drive reasonably and stay off the go pedal you can get better MPG out of a 4v carb than a 2v carb".

I don't really have an opinion on this one way or the other since when it comes to mustangs I am all about power and speed first, economy second.

 

first off the 220hp was the old gross hp rating so if you were talking 275-280 hp in the old terms then a stock 5.0 will do that. A stock 2bbl 289 rated as we do today would really be about 150-160 hp at the flywheel. If you want 275-300 hp s.a.e from your 289 then you will need head,cam,intake,exhaust upgrades although you can throw a big cam at it (with proper valvetrain mods) intake and exhaust upgrades and make close to 300hp but only at the upper rpm's at the expense of low end and drivability. I would definetly go the 351w as you will get an instant 60hp/60 ft lbs even in stock form, add a cam/intake/exhaust to the 351w and it will blow the 289 with 1/2 throttle. Heres a cheap but effective 351w build, stock shortblock, 9.1 compression, comp cams 268h cam, port match the intakes and exhausts, add 194 160 chevy valves and do some valve pocket porting and blend them into the ports, 1 5/8 headers, wieand stelth intake and a 600-650cfm carb, this will give you at least 300-330 hp and about 380-400ft lbs of torque, low end will smoke the tires off your stang and fuel economy will be better than the 289 2bbl if you keep your foot out of it. You will have more power at 1/2 throttle with the 351 than the 289 at full throttle also if you use the 289 c4 and converter it will give you a slight bit more stall.

How do I know this? I did this exact swap and my friend and I had almost the exact same build on our 289's but he had more cam but we both had the same ported 351w heads, I swaped my heads onto the 351w built just like I stated, before that we used to run pretty equal (his FB, my vert) although I would take him off the line and he would pull 1/2 car lenght at top end, after the 351w I'd take him off the line even at part throttle and he would quit after I pulled about 4-5 car lengths from him. With my 289 I got about 15 hwy mpg's, with my 351w 18-19 mpgs was the norm. With my new 408 and an AOD I can still get 18mpg's.

 

now heres the issue with the whole, using my 95 351w. its purpose is to serve as the powerplant for my 92 fox. being as its easier to gain hp, my goal with N/A on the 351 is about 480-500rwhp. and i know that isnt gonna happen with the 302. and i have no intentions of buying another 351w i have a bunch of random A.M. parts for the 351w in EFI form.

so what we are all saying is to stretch my 70 302 another 100hp will be more costly than i care to invest.

 

If heads, intake, and cam are too expensive, then yep. That is the only way to truly make more power. You got to get more air in the motor.

 

I spent a lot of time shopping around and kept my engine cost pretty reasonable.

What I went with is ported GT 40's, Weiand Stealth intake, Holley 600 and 214 / 224 cam. I was going to add an HEI type distributor that I picked up but it wouldn't fit so I sold that and used my stock one with a Pertronix added. Running pretty much stock exhaust for the time being.

Off of the local Craig's list over some time I found the valve covers and intake for about $140, found the heads already machined and ported but never installed on a motor for $500, found the carb on this site for about $100, etc, etc.

It's a pretty good little engine for street use, sounds pretty good with a slight lope but nothing over the top. The horse power is much better now than the worn out old stock 2 bbl / 289 that was in the car when I bought it.

My next planned upgrades are adding a performance minded valve body to the tranny and I have been looking at some servo kits as well.

Here's the most recent picture of my bay....you'll have to excuse the fact my wires are all over the place. I really need to get some sort of clip to make them look more organized...

 

alright so the answers pretty clear, the entire topend will have to be Aftermarket, no 2v carb. and possibly change piston/size

i was hoping i could do this with stock parts or $1,000 but doesn't look like thats gonna happen ok thanks guys