build drivetrain suggestions: 302-V8 vs 300-I6 ???

[tdkask]

Thanks. I can't keep up... responses while I respond...

I'd love to see photos of the swaps some of you guys have done. As much info as there is here, I've noticed there aren't a lot of swap write-ups, relatively speaking.

If I didn't consider it blasphemous Id even throw in the idea of a Jeep 258 with 4.0 head and EFI, AW4, NP231 Crawlbox and D300... but it's just not right in a EB... and still a very long I6.

Either way, the begin of all of this was the fact that I am looking to purchase a 71 with a 170 and in the coming months will surely want more than the 170. I think I will have to decide based on availability at the time and budget, but wanted to consider a I6. A 300 may definitely be the way to go, but the 250 just might be a good trade off. Again, thanks a lot guys. Keep it coming.

 

[gbkeith]

As much info as there is here, I've noticed there aren't a lot of swap write-ups, relatively speaking.

I think it's because of the unique nature of the swaps. Over the last few months I've been researching everything I can find on putting a 4bt into an early Bronco. It's been done, but everybody has done it a little differently. A 300 swap is sort of the same way. It's been done by people who had their reasons, but they've had different reasons and different goals in mind. Read anything you can on what they've done, and figure out how best to suit what you want. That's part of what makes it interesting. It wasn't a factory option, so instead of a simple step by step process of switching things over, you get to play with things and do it how you want.

I'd originally thought to put a 4bt in as simply as possible. Now I'm planning on swapping and moving axles and all sorts of things. It's not a car, it's an adventure.

If it's what you want, I say stick a 300 in there. Have fun with it and see what happens. I just saw a thread on bronco chat where somebody put a supercharger on an inline 6. Whatever you end up doing, it isn't any crazier than what somebody else has already done succesfully, so don't sweat it.

 

[bmbm]

250 six cylinder

The engine mounts are basically the same if you look at the 250 block compared to the 170 you will see. Which brackets do you mean?
It is a jeep trans and AA kit. I think the trans swap was about $1800 with the bell, flywheel, clutch and etc. To save money consider the 4 speed that came with the mid 80's f150 with a 300 six as the 250 has a small block bell housing pattern. Someone on here had one for sale recently.

 

[Revelation]

Here is my thread on the Chassis build on mine, should give some insight into the 300.
http://classicbroncos.com/forums/showthread.php?t=97476&highlight=rolling

 

[BIGMH1]

Loving my 170c.i. np435 combo. Plenty of speed on the road and crawl on the trail.

 

[tdkask]

BIGMH1,
I just have to think that though a 170 will get there, it has to be the bottom end spectrum of power. Even if compensated with more gearing in the np435 it leaves room for improvement. Now I guess that could be said of a well built 351W too, but I'd like to get a little more out of it in the end. I was skeptical even to buy a 170 because I was afraid it'd be a lot of work to upgrade and I wouldn't be happy with what was already there. Also, I ultimately want a automatic too. I think either a well built 250 or a moderate 300 will be great in the end. A 300 has a cool factor too, IMHO, so I would love to do that.

I wonder about an EFI 4.9? Then I can get the same torque upside down. And maybe even find a donor with suitable pulleys/brackets to run factory add-on AC.

 

[fungus]

I really like the idea of an EFI'd 4.9l. There's an early to mid 90s FSB over here I've got my eye on that's got the efi 4.9l & 5 spd manual OD trans in it... Considering they even put that 300/ 4.9 in some F-250s, you know it's gotta be a stump puller.

 

[bad 68]

The 300 only feels like it has more Torque than the 302 because the 300 has no HP.
It has no HP because the torque drops off at such a low rpm thats where you Have to run it. You will get better highway fuel mileage at say 2800 rpm with the 302 than you will the 300. Bigger bore/pistons do not help with fuel efficiency. The two engines have nearly identical Cubic Inches.
Best mileage your going to get is with a bone stock Mustang HO Fi 5.0.
Most fun your going to have is with a well built 351W or a stroker 5.0.
And you guys that say wheeling is all about low end I disagree.
It's about having a lot of gears to pick from, and an engine that chugs when you need it to, and comes alive and screams when you want it to! I have won a few bad sections because I could pull a higher gear and power up what the sixes couldn't.

 

[Revelation]

[Youtube]YyxZqWRYn24[/youtube]

 

[tdkask]

That's cool... But very much a traction comparison too.

All things considered and if almost the same with almost the same economy, the I-6 would look cooler.

fungus, the idea of a FSB 4.9/auto(for me)/and TC swap would be great. there's a local guy who will sell the 4.9 with all accessories and harness and computer for $500... I could probably get the exhaust manifold too... then just route exhaust from there.