roller or flat tappet cam motor build

[MikeKC130J]

Ok folks,
I have recently purchased my 3rd bronco, it runs fine, however we all know we are never content with what we have, always looking to upgrade. I purchased the green turtle from Randy at driven 4x4 out of Phoenix. Great guy and has a lot of great stuff, the bronco has the original 302 motor 74000mi ish, I would like to go with a 351W, but I'm under the impression I can get close to the same gains by stroking the original 302. I can get a great deal on a roller 302 and have it stroked I really don't know the pros and cons of a roller VS a Flat tapped. I think its easier to just rebuild and stroke or get a roller motor and stroke it. I won't be doing any crazy off roading (mild), in a few years my son will be driving it to school. I will be updating the Manual 4 speed gear banger to a 4r70w when I decide to up date/ up grade. I will be updating the suspention to either 2.5 or 3 in with progressive rate springs. I will be running 33's, Ill have to upgrade the gear set I believe I have 3:50's probably go with 4:11 with some sort of locker. (front Or back?). defiantly going to do the front disc brake conversion, it will be my second one I've done. Im also going to be going EFI which do you prefer the Sniper or Fitec?

 

[nvrstuk]

Sounds like all kinds of mod's soon to happen on this Bronco!! : )

Roller cam allows m u c h steeper ramp rates than flat tappets allowing noticeably flatter torque and power curves... course we are talking in a DD type rig where you want to "set it and forget it" right?

I'd go 351W hands down...torque is what 90% of us want in our Broncos to get the heavy beast moving...

Then stroke the roller block 351W and have the best of it all...

 

[sykanr0ng]

Aside from not needing special oil additives the main advantage to the roller cam is that they open and close faster due to the roller lifters not digging into the lobes of the cam like the edges of flat tappet lifters would if the lobes were made as steep.
This allows longer times under the maximum lift for the cam without needing to increase the duration to get it.

 

[MikeKC130J]

Sounds like all kinds of mod's soon to happen on this Bronco!! : )

Roller cam allows m u c h steeper ramp rates than flat tappets allowing noticeably flatter torque and power curves... course we are talking in a DD type rig where you want to "set it and forget it" right?

I'd go 351W hands down...torque is what 90% of us want in our Broncos to get the heavy beast moving...

Then stroke the roller block 351W and have the best of it all...

Yes exactly just like Ron Popeil.. set it and forget it! DD I had a 351W in my last 75 but I retired from the Marine Corps and had to sell it for a down payment on a house. I did not drive it 150m before I had too sell. ill be homeless next time. anyhow stroke the Roller 351W to 408 and put an EFI ( sniper Fitec?) , gears 1" body lift and 2 in suspension lift and let her be for a while! Thanks I'm digging it!!

 

[cldonley]

Hmmm...408 stroker Bronco for a high schooler. You are a brave man!

 

[broncnaz]

While a roller motor is a little more desireable there is no real noticeable gain from going to one. While a roller cam is more or less easier as far as engine break in theres really nothing wrong with a flat tappet. There are still millions of flat tappet engines running around today and people are not putting additives in there oil. There cams are not failing. Although I would suggest that you do just for a little extra insurance.
EFI is a nicety and can be put on any engine so you could even start out on the current 302 and put it on the next engine when the time comes.

Its all up to you as to which way to go. I have several engine options to go with but my 73 will get a 302 again and it will have a stock bore. One of my engines was out of a bronco but mileage was unknown when I pulled it apart it was in pretty good shape with next to no wear on the bores so Im sticking with stock bore so this engine will live another life before getting bored out. While a 351 or a stroker does yield more power a mild 302 will more than do the job.
Just keep in mind the more power you make the more upgrades that will be needed. while you mentioned gearing and lockers axle shafts themselves will also need a upgrade.

 

[Broncobowsher]

Ford developed the stroker 302 a long time ago. And put a whole bunch of good engineering behind it. Called it the 351W. If you have ever been inside both engines you will see the 351W has a lot more engineering into making it better. Hands down the 351W is a better engine. Unless you are making a lightweight race car, then I will accept the lighter 302 based engine and all the smaller and daintier parts inside. But a Bronco isn't light, and you are not building a race car engine for a high school kid. Power is built in airflow, mainly the heads. Top end packages will make either engine comparable.

Before going that far, why not just look at the engine you have now. At 74k it probably needs a timing chain. That would likely fix things for long enough for your kid to get through high school.

 

[MikeKC130J]

All great recommendations thank you i will take all into account. Thank you

 

[blubuckaroo]

The 351W isn't a stroked 302 by any means! It's more than the cubes.
Equip a 351W with the same stuff as a 347, and the 347 will run circles around the 351W.
They have different attitudes.
The difference is the weight of the crank.
Now, I'd never say the weight of the crank doesn't have some benefits. It does help retain inertia, much like a heavy flywheel.
It's just that how you need to decide how you want the vehicle to perform. The difference is peppy vs torqey.

 

[The Far Side]

Dibs on the 4speed when you swap!!! ;D

 

[Glass Pony]

Taken from Tom Monroe's "How to rebuild small block ford engines".
351W- The 351W engine marks the first major change of the small block ford's block. The deck height distance from the center of the crankshaft main bearing to the cylinder head was raised 1.274 in. to accommodate an additional 1/2" stroke. Deck height was increased from 8.206" to 9.480". The 4.00" bore was retained. To handle the additional bearing load resulting from the increased engine displacement, the main bearing diameters were increased from 2.25" to 3.00".

 

[Broncobowsher]

Don't forget the main bearing caps and head bolts were upsized from 7/16 to 1/2".
A 302 block is typically known to be good for 400 HP before splitting apart, the 351W block is usually good for 700 HP.

 

[Glass Pony]

Don't forget the main bearing caps and head bolts were upsized from 7/16 to 1/2".
A 302 block is typically known to be good for 400 HP before splitting apart, the 351W block is usually good for 700 HP.

Forgot about that one. Did the main bearing cap bolt's size get increased also?
Duh... I better put my glasses on.:-[

 

[Broncobowsher]

Yes, just like the head bolts. From 7/16 to 1/2".
The aftermarket 302 blocks typically have the heads and mains drilled and tapped for 1/2" bolts. I checked on the last 302 I built (happen to be a stroker but that was due to packaging limitations, old Rangers are a tight fit with a 302 especially when you want to keep the A/C). The root diameter (what you drill the hole to before tapping) is smaller then the 7/16 threads. If I would have helicoiled all the holes it would probably have worked, just used ARP studs and called it good enough.

 

[pcf_mark]

Roller every time. Tolerant of start up / break in problems, less wear, more power. Reduced friction gets you a bit of power but the real power is you get a fast acting cam that will build more torque and power with the same driveability.

 

[sanndmann3]

Roller every time. Tolerant of start up / break in problems, less wear, more power. Reduced friction gets you a bit of power but the real power is you get a fast acting cam that will build more torque and power with the same driveability.

What he said. I did a flat tappet 351W years ago and wish I had started with a roller block. Also wish I had stroked it to 408 or bigger but oh well...

 

[blubuckaroo]

Certainly a roller motor is preferable, but don't be afraid of a good deal on a flat tappet build. As long as you're aware of the break-in requirements, you won't have a problem.
Also, there are a lot more cam profiles available for flat tappet cams.

 

[rguest3]

Which ever motor you decide to build, drive your bronco as is for now. Have a nice 5.0/347 (easiest to install) or 351w (May need 1" Body Lift for stock hood clearance) built and drop it in when complete. Less down time.