Will I lose low end torque by using an B303 cam with a mild 306?

[ssp.interceptor]

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[ssp.interceptor]

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[rjcooperss396]

Here are some examples for the gearing.

3.73 gears with 27 inch tire.
65 mph = 2000 rpms
75 mph = 2300 rpms

3.73 gears with 31 inch tire.
65 mph = 1700 rpms
75 mph = 2000 rpms

4.10 gears with 31 inch tire.
65 mph = 1900 rpms
75 mph = 2200 rpms

4.56 gears with 31 inch tire.
65 mph = 2150 rpms
75 mph = 2500 rpms

TBM, when you're ready to port your heads, I have a build thread on my conversion with a ton of pictures of the porting I did if you want to copy what I did on my heads.

http://www.explorerforum.com/forums/showthread.php?t=325764

 

[TBMounty50]

Tires are definately causing some of that for sure, gears are stock 3.73. I'm waiting till I'm sure that 31-10.50s are big enough. Don't want to regear again if I re-skin with 33's.

As far as the trans goes, I'm at 165K now so a rebuuild is at least minimum and I know I'll spend more in upgrades cause I can't leave well enough alone. By the time that is said and done I could have bought the 5 speed, flywheel and new clutch. Then I'll have full control and most importantly, be happy. Not to mention having a unique combination. I had a guy crawl under my truck to make sure the transfer case shift linkage was actually attached to something!

Thanks for the link on your heads rj, I'm going to check it out now. I still need to pick up a pair of buildable P heads. Only ones I've got are on the truck and I can't have that kind of down time. I've got a pair of E7's that need to go in with the next load of scrap. Actually, I may keep one of them in case I ever get a boat, if you get my drift.(pun intended)

 

[rjcooperss396]

Tires are definately causing some of that for sure, gears are stock 3.73. I'm waiting till I'm sure that 31-10.50s are big enough. Don't want to regear again if I re-skin with 33's.

As far as the trans goes, I'm at 165K now so a rebuuild is at least minimum and I know I'll spend more in upgrades cause I can't leave well enough alone. By the time that is said and done I could have bought the 5 speed, flywheel and new clutch. Then I'll have full control and most importantly, be happy. Not to mention having a unique combination. I had a guy crawl under my truck to make sure the transfer case shift linkage was actually attached to something!

Thanks for the link on your heads rj, I'm going to check it out now. I still need to pick up a pair of buildable P heads. Only ones I've got are on the truck and I can't have that kind of down time. I've got a pair of E7's that need to go in with the next load of scrap. Actually, I may keep one of them in case I ever get a boat, if you get my drift.(pun intended)

I'm running 4.56 gears with 33's on my Explorer. They worked well even with the 160hp 4.0 but I only used it to tow and couple times and it was only a light trailer with one quad on it. The gearing and tire combo is a higher ratio than it was with the stock 3.73 gears and 27 inch tires so I'm turning a little higher rpm at any given speed now. If fuel millage is really important to you it might decrease your mpg but it will definitely help when towing.

 

[Joe Dirt]

This is quite entertaining, especially since I know who "the new guy in post #45" is, and it makes it all the more entertaining.

Sadly, even this forum is starting to go like this:

"I built this, so it's right."
"You built that, and I didn't, so it's wrong."
"I will without question defend my combination of parts, right or wrong, because I built it."

It's entertaining to me. It's also why I don't contribute to offroad threads, or get involved in performance threads, both of which I could add some good input. It's not worth the hassle anymore.

The "new guy in post #45" has owned more cars than Jay Leno, and I've seen plenty of them run. I'll just add that they're not jokes, and that either of us could build something for pennies on the dollar that would run just as hard as anything tossed together with parts bought out of the Summit catalog. We've done it before, dozens of times. It's just how the build game works.

Never assume that because some "new guy in post #45" only has <gasp!> only 70-whatever posts that he doesn't have a clue what he's talking about, it's incredibly insulting and disingenuous.

 

[ssp.interceptor]

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[Joe Dirt]

"I just got a junkyard explorer motor with a STOCK cam. Wanna run um'? I just what to see how badly I get beat."

AAAAHHHHHH.... The Good Old Days....

Fixed that for ya...

 

[rjcooperss396]

Fixed that for ya...

Are you trying to say a stock cam Explorer engine isn't going to make good low end torque?

 

[Joe Dirt]

No, you can make good torque with a stock cam inside of a P-motor, and an HO cam is a stock cam... Back in the day we ran plenty of stock cams in our P-motors and consistently walked away from aftermarket-happy guys... It would seriously piss off some people when they found out not only what was done to the motors but how little was spent to beat them.

 

[ssp.interceptor]

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[rjcooperss396]

I know that. I like to listen to guys tallk about how fast their cars are until I race them at the track. I've been building engine since I was 17 and I'm 40 now. My '69 Chevelle in the videos was my first car that I bought at 16. My dad helped me build the 396 when I was 17. Back then it ran a best of 14.10 at 99mph. With the current 454 it's run a best 10.01 at 133. The next 454 I build for it is going to have a centrifigul blower and I plan to have it running 9's at the track but still be able to run pump gas on the street. Right now I have to run it on 100 octane.

I've never had an engine with a custom cam, every engine I've ever built has had a stock cam or an OTS cam. However, my buddy is friends with Ed Curtis so I will probably be using a custom grind from him in the next engine.

 

[ssp.interceptor]

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[ssp.interceptor]

"I just got a junkyard explorer motor with a STOCK cam and it's SPEED DENSITY. Wanna run um'? I just want to see how badly I get beat."

AAAAHHHHHH.... The Good Old Days....

You missed something...

 

[TBMounty50]

Thanks for the experience all. I think I've been swayed to retain my stock cam and a couple hundred bucks. Let me pose this question, What effect will 1.7's have on the characteristics of that stock cam? I've heard they will actually shift the powerband up, and would be counterproductive for what I'm trying to do.

 

[TBMounty50]

BTW, I'm not one of those who falls for all those little b\s parts and their exaggerated gains. Those numbers are rediculous. I have a cold air intake cause my stock paper filter was dirty. I have exhaust because, well, I couldn't hear the one supplied by the factory. Neither one of those made the needle of the "butt dyno" twitch. I did pick up an extra mile per gallon though.

 

[ssp.interceptor]

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[rhauf]

Thanks for the experience all. I think I've been swayed to retain my stock cam and a couple hundred bucks. Let me pose this question, What effect will 1.7's have on the characteristics of that stock cam? I've heard they will actually shift the powerband up, and would be counterproductive for what I'm trying to do.

as you probably know, that will only give you more lift.

more lift with small stock heads will decrease torque, and the added lift will provide little if any added flow so don't expect much higher rpm gains.

once you lift a valve more than a certain distance (relative to the valve diameter) you gain nothing. so higher lift is only beneficial with large valve heads.

also keep in mind that higher ratio rockers increase stress on the cam and lifters. which is guess isn't a huge deal for a roller cam... it will also lower valve float rpm (although that may also be a non issue as it will still do 5500 or more)

as for the "letter cams".. personally i think they are great. but they don't produce much low rpm torque. they are a mid to high rpm cam. for good performance in a heavy vehicle, you'd need a matching torque converter (cam range for a b303 would be say 2700rpm and up, so you'd need about a 2500rpm stall)

 

[TBMounty50]

I know It wasn't aimed at me, just saying I agree with you. Those parts have a place as supporting roles at certain power levels.

 

[TBMounty50]

as you probably know, that will only give you more lift.

more lift with small stock heads will decrease torque, and the added lift will provide little if any added flow so don't expect much higher rpm gains.

once you lift a valve more than a certain distance (relative to the valve diameter) you gain nothing. so higher lift is only beneficial with large valve heads.

also keep in mind that higher ratio rockers increase stress on the cam and lifters. which is guess isn't a huge deal for a roller cam... it will also lower valve float rpm (although that may also be a non issue as it will still do 5500 or more)

as for the "letter cams".. personally i think they are great. but they don't produce much low rpm torque. they are a mid to high rpm cam. for good performance in a heavy vehicle, you'd need a matching torque converter (cam range for a b303 would be say 2700rpm and up, so you'd need about a 2500rpm stall)

Thanks for backing up my suspicion. I've given up on the B cam for my truck.