Hey I've been working on my buddy's 91 rs with a 305 and My other friends have a few late 80's 5.0 GTs stick shifts. I was curious what you guys think about his combo if he can stay with the 5.0 M u s t a n g s? What I did to his motor,

Carburated with a 600 cfm edelbrock
performer EPS manifold
mildly ported 601 heads with bigger valves and better springs for the cam.
ZZ4 hydrallic roller cam (.474/.510 lift with 208/221 dur @ .50)
hedman shorties with Y pipe and catco cat with a dynomax 2.5 cat back.
3.27 posi with a 700r4 stock stall.
Stock but healthy bottom end.

Should be up and running in a few days, i'll report back on the final results.

 

With those mods I would say that the 305 will be faster. That is if you get them all dialed in.

 

Better tell your friend to be damn careful with that stock bottom end. That car is going to want to rev a decent amount. I'd say 6000RPM is his cut-off for sure.

I also agree if the car is dialed in right, it should be running quicker than the Stangs...assuming they are stock.

 

Depends whats done to the 5.0. They can be made extremely fast with very little done. I would say against stock and mild ones, that combo should holds its own well, but once the mods on the 5.0 start to get more serious it could be lights out for the 305!

 

Well, The ford 5.0 that I have in mind has a couple minor mods done, A/C removed, underdrive pulleys, mechanical fan replaced with a electric one, cold air intake. He is soon getting headers, duel cat h pipe with 2.5 duels. My buddy with the RS is going to run this 305 untill it breaks, then we will drop a 355 in. I think he will do ok. He going to get it dyno tuned once its back on the road. Its kinda funny because he works as an installer at a import tuner shop but He wants to build up this camaro instead. He knows imports in my group of friends, but I am the chevy guy.

 

umm i hate to burst your bubble but that high of lift cam in a 305 is going to start making power at like 4,000 rpm not to mention the stock castings can't even handel that high of lift They're only rated to .500 lift.

 

That cam wil be fine in a 305. It should make strong power throughout the power band. The stock valve guides are limited to .480" max. Most stock heads however are even less than that.

 

The heads are fine for the lift, the machine shop prepared them, and did what I told them to do, I checked and they look fine. The cam is only a 208/221 duration. and duration is what makes the loppiness and hurts streetability. My 355 cam is a 224 duration and its not too bad and gets good vacuum, I know a 305 will be hurt more by duration but on the intake side its only 208. I am not too worried about too high of a power band. He is pretty excited about the car, we should get it running tonight. then We need to set up the TV and get the lock up switch installed. Then we can drive it.

 

Just line them up and race. Best two out of three. Please post the results.

 

i wana race your friend that would be fun

 

Am i missing something?

"ZZ4 hydrallic roller cam (.474/.510 lift with 208/221 dur @ .50)"

You're saying your going to use a cam that has .474 on the intake and .510 on the exhaust? thats huge. I'm sorry i didn't think that was possible.

 

That's not huge, it's rather tiny as far as performance cams go.

 

It is not huge but it is in the medium range. It is too much for untouched valve guides on stock heads but the duration isn;t too much to handle. Don't get to caught up in the lift. A stock LT4 cam with 1.6 rockers will exhibit numbers close to that.

 

Well it runs! We got it running about a hour ago. We got slowed down by an oil leak that need to be fixed and having trouble with the stock fuel pump not running, we finally got it to run. The cam is not too bad, in fact it doesnt have much of a lope at all at idel. It fired right up after we got the fuel issue sorted out. I got some questions to ask but I'll ask em in the proper thread. I'll post the race results next week once we get it to be able to drive. The trans still needs some sorting out.

 

Thats nuts makes me feel like the .420/.442 cam i got in my 305 is *****, but then again it is. I'll be swapping its soon. Also does anyone know what lift the stock springs experience coil bind at?

 

Stock un-touched GM castings range from .460" to .480" max lift for guide clearance. Don't worry about valve springs since you will need to buy ones matched to the cam. If you want to go with a big cam you will need to have do some work on the heads.

 

What exaclty would they have to do to the valve guides? also would they have to do anything to the spring seats?

 

They won't have to touch the seats but you will need to have the guides machined. THis will allow for greater spring travel so that you can run higher lift cams. You should also have the heads drilled and tapped for screw in rockers. The pressed in stock type can pull out really easy once you start using a high lift cam.