Confused yet again

[mudchucker]

OK guys, i have posted i few times on here about if Speed Density or MAF is the way to go. Of course, i have found that there are pros and cons to both sides. So now i have a few more detailed questions. I have a 91 lincoln 5.0 and here is what i plan on doing- i am going to put an E303 cam in, i have new valve springs (the double kind), heads off of a 91 mustang, intake both upper and lower from a Mustang and headers for a Mustang. I am trying to upgrade to roller lifters and it seems there are both 1.6 and 1.7 as the common ones around. How do i know which to get or which would you guys recommend? Also, i purchased 2 books on how to upgrade 5.0 engines. Now in these books it says that changing over to an E303 cam without converting to MAF will kill the engine in a fairly short amount of time, it won't hold idle and it will actually decrease in power. Now after searching and talking with a few people from this board, i have found that many people still run the SD and have no problem at all. I am just a little confused and need a little help with what is realy going on. I would love to keep it SD, because that is what i have, but i also would like to get some better performance out of it. I welcome your comments and testimonies please!

[Dark_5.0]

Originally Posted by mudchucker

OK guys, i have posted i few times on here about if Speed Density or MAF is the way to go. Of course, i have found that there are pros and cons to both sides. So now i have a few more detailed questions. I have a 91 lincoln 5.0 and here is what i plan on doing- i am going to put an E303 cam in, i have new valve springs (the double kind), heads off of a 91 mustang, intake both upper and lower from a Mustang and headers for a Mustang. I am trying to upgrade to roller lifters and it seems there are both 1.6 and 1.7 as the common ones around. How do i know which to get or which would you guys recommend? Also, i purchased 2 books on how to upgrade 5.0 engines. Now in these books it says that changing over to an E303 cam without converting to MAF will kill the engine in a fairly short amount of time, it won't hold idle and it will actually decrease in power. Now after searching and talking with a few people from this board, i have found that many people still run the SD and have no problem at all. I am just a little confused and need a little help with what is realy going on. I would love to keep it SD, because that is what i have, but i also would like to get some better performance out of it. I welcome your comments and testimonies please!

Reguardless of wether or not you keep the speed density or convert to mass air the E-cam wont do you much good in a stock engine.

1.6 and 1.7 is the roller rocker ratio. With the E-cam and stock heads 1.6 roller rockers is what you would want.

Mass air is better but you can run 11's on speed density.

[mudchucker]

As always, thanks Dark 5.0. i do have one more for you. When i put on 1.6 rollers will the stock pushrods be ok, and if not should i go ahead and get new? How much do new rods run?

Thanks again

[Dark_5.0]

Originally Posted by mudchucker

As always, thanks Dark 5.0. i do have one more for you. When i put on 1.6 rollers will the stock pushrods be ok, and if not should i go ahead and get new? How much do new rods run?

Thanks again

Inspect the stock push rods and if they look good make sure none of them are clogged and re-use them. New push rods run 60-100 dollars for good ones.

[mudchucker]

Originally Posted by Dark_5.0

Reguardless of wether or not you keep the speed density or convert to mass air the E-cam wont do you much good in a stock engine.

1.6 and 1.7 is the roller rocker ratio. With the E-cam and stock heads 1.6 roller rockers is what you would want.

Mass air is better but you can run 11's on speed density.

Dark, what would you recommend for modifications to get the most gains with the E-cam and speed density?

[~The Jester~]

HEADS.

and an intake. Big cams don't do much good if the intake/exhaust sytem can't utilize what the cam brings to the party. That intake and stock heads can only flow so much air/fuel, no matter how far the valve opens, or how long it stays open. That's where you run into "killing" the engine with too big of a cam. Ya loose port velocity. Think of it this way. You have a 1/2" garden hose that you wash your car with. Inside the house, there's a 1/2 copper line that feeds the 1/2 spigot. With me so far? What would happen if all we did was switch the spigot with a 3/4" one? Might get a little better flow (read as power) but prolly not. What happens when we put a 2" valve in there instead? The water gets lost in the big valve now, and not much comes out the hose, we lost our velocity.

A VERY crude metaphor, but you get the idea. Simply adding a cam nets you very little horsepower. When selecting a cam, planning for the future is a good idea. In fact once you add the other goodies, that new cam will keep adding to the mix.

Make sense? I hope so. Just tryin to help ya out!

[mudchucker]

Originally Posted by ~The Jester~

HEADS.

and an intake. Big cams don't do much good if the intake/exhaust sytem can't utilize what the cam brings to the party. That intake and stock heads can only flow so much air/fuel, no matter how far the valve opens, or how long it stays open. That's where you run into "killing" the engine with too big of a cam. Ya loose port velocity. Think of it this way. You have a 1/2" garden hose that you wash your car with. Inside the house, there's a 1/2 copper line that feeds the 1/2 spigot. With me so far? What would happen if all we did was switch the spigot with a 3/4" one? Might get a little better flow (read as power) but prolly not. What happens when we put a 2" valve in there instead? The water gets lost in the big valve now, and not much comes out the hose, we lost our velocity.

A VERY crude metaphor, but you get the idea. Simply adding a cam nets you very little horsepower. When selecting a cam, planning for the future is a good idea. In fact once you add the other goodies, that new cam will keep adding to the mix.

Make sense? I hope so. Just tryin to help ya out!

Ok, that makes sense, i have never thought of it in those terms (which totally makes sense now). Would you port and polish what is there, or would a nice aftermarket be a better choice? Thanks for your help Jester.

[Ieatcamaros]

The few extra dollars for the aftermarket heads is well worth it compared to the cost of porting a set of stock heads.

[bmxmon]

i ported my own heads. It took forever, and i probably spent $50 on tons of grinding bits, but it *should be worth it. (havent ran the engine yet)

[Ieatcamaros]

I should add that if you pay to have your stock heads cnc ported and larger valves added. I wasn't really referring to just porting them with a die grinder. Porting with a die grinder is definitely worth it, IMO. It could cost more than $700 to add larger valves and cnc port stock heads. You can get a good set of used trick flow twisted wedge on ebay for that price and have a much better head.