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Discussion Starter · #1 ·
This is actually a 289 for a 68 Bronco that I'm building so my apologies tor the lack of Mustang content. The short block is with my engine builder and so far have decided on KB116 domed pistons to go with the stock 63cc heads which I have ported on the exhaust side. I'm hoping this will get at least 9.0:1 -9.5:1 compression for a little bump in power. I'm not looking for super high HP since it's otherwise a stock Bronco but just a fun cruiser. Any recommendations on which intake, carb, exhaust and cam would be very helpful.
 

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This is actually a 289 for a 68 Bronco that I'm building so my apologies tor the lack of Mustang content. The short block is with my engine builder and so far have decided on KB116 domed pistons to go with the stock 63cc heads which I have ported on the exhaust side. I'm hoping this will get at least 9.0:1 -9.5:1 compression for a little bump in power. I'm not looking for super high HP since it's otherwise a stock Bronco but just a fun cruiser. Any recommendations on which intake, carb, exhaust and cam would be very helpful.
Bear in mind that while the combustion chamber volume is larger on the '68 head (63cc vs 53.5cc), the valves are in the same place so be very careful checking your piston-to-valve clearance.
 

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If your goal is reliable cruising and good low end torque, you'll be well served with the stock Autolite carb and intake, and an off the shelf cam with a little more lift and duration, more on the exhaust side, that will certainly do it without taking your wallet off-road.
 
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Discussion Starter · #5 · (Edited)
I'm not opposed to the stock carb and intake, definitely wanting to keep the engine as stock looking as possible with a little bump in power. Preserving low end torque is what I'm looking for.
 

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Anew, you might consider running an Autolite 4100 on top of a Weiand 8124 Warrior intake. much improved over stock, but not crazy. What, if anything, are you doing to the heads ? LSG
 

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Discussion Starter · #8 ·
Thanks for the tip on the compression calculator.

I'll definitely check that intake and carb.

I got rid of the thermactor humps and smoothed out the exhaust ports. I'm also planning to port match the heads.
Stock valves.
 

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The 4100 will be expensive enough and I wouldn't bother with it on a 4x4 for low RPM grunt power, unless you think you'll need it for passing slow moving tow rigs on the way to the trail ride. My brother has a 75 Scout with a 345 and mentioned a couple times putting the IH 4V intake on it with a 4 barrel, or maybe a Sniper. I asked why if it would likely never see more than 3000 RPM and 55 MPH. That engine was built to crawl over stuff and tow heavy stuff. I put an Autolite 2100 on it, set the choke, and it starts with a bump of the key. Best carb ever for a truck.
As far as higher RPM performance, the big brother is a GREAT carb; I have one on my 66 Mustang and I love the sound of the back barrels open, but it's a rare occasion.
As far as exhaust, duals are sweet, 2 and 1/4" is plenty, make sure it's aluminized and you can go stainless if you have the money. The Bronco is a short truck so it's like having a short barrel gun, they can be LOUD. I would go with a pair of glass packs for vintage sound and some pop, or some turbo style mufflers for the vintage growl at idle but not too much volume and no drone at speed. Flowmasters sound good on my neighbor's Jeep with a small block V8, some guys and girls just don't like chambered mufflers for the metallic sound or droning some get on longer cruises at certain RPM.
 

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Discussion Starter · #11 ·
Anew, hard seats under exhausts ? Are the valves in good enough shape to be ground and re-used, or do you need new ones ? What're your camshaft plans ? LSG
The heads don't have hardened seats. The valves are new.
I was thinking something like an "RV" cam but would love suggestions.
 

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Discussion Starter · #12 ·
The 4100 will be expensive enough and I wouldn't bother with it on a 4x4 for low RPM grunt power, unless you think you'll need it for passing slow moving tow rigs on the way to the trail ride. My brother has a 75 Scout with a 345 and mentioned a couple times putting the IH 4V intake on it with a 4 barrel, or maybe a Sniper. I asked why if it would likely never see more than 3000 RPM and 55 MPH. That engine was built to crawl over stuff and tow heavy stuff. I put an Autolite 2100 on it, set the choke, and it starts with a bump of the key. Best carb ever for a truck.
As far as higher RPM performance, the big brother is a GREAT carb; I have one on my 66 Mustang and I love the sound of the back barrels open, but it's a rare occasion.
As far as exhaust, duals are sweet, 2 and 1/4" is plenty, make sure it's aluminized and you can go stainless if you have the money. The Bronco is a short truck so it's like having a short barrel gun, they can be LOUD. I would go with a pair of glass packs for vintage sound and some pop, or some turbo style mufflers for the vintage growl at idle but not too much volume and no drone at speed. Flowmasters sound good on my neighbor's Jeep with a small block V8, some guys and girls just don't like chambered mufflers for the metallic sound or droning some get on longer cruises at certain RPM.
Great stuff here, just the kind of information I'm looking for.
Would you recommend stock exhaust manifolds or something with more flow?
 

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Anew, I'd choose a header of some kind if it were mine. The factory castings are sorta okay, but they also have the little two inch flange on the ends, which just isn't big enough. If you shop around, you should be able to find a decent 4100. I paid 125$ for my latest 1.12 version. On the heads, are you willing to help them abit ? If you haven't installed your new stock valves, perhaps you can return them. In a normal SBF head, you can dramatically improve breathing with bigger valves. In your situation, I'd use the intakes and exhausts from a 69~70 351W, 1.84 intake and 1.54 exhausts, and I like to put hard seats under the exhausts. We've always used SB1625-1 seats. When you assemble, throw your umbrella seals in the trash bin and use 35-305V stem seals. I'll get you the part numbers for the valves if you want. The price difference is just PENNIES between the little 1.78 / 1.45 and the nicer 1.84 / 1.54 valves. If you're having a valvejob done, it is a very easy upgrade.

For a camshaft, consider a Comp 35-255-5. You'll have to rewire the secondary leads on the dizzy to 13726548. Easy. When I was back to work a few weeks ago, we JUST DID this exact build for a 302 in an early Bronco. Works VERY well. LSG
 

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@LSG has excellent advice, as always.
I don't care for headers for a street cruiser myself, because they're not as quiet as cast iron manifolds, and they tend to leak or rust through.
For a little more flow, go with a pair of 64-68 289 HiPo manifolds (available as a reproduction) and do a little port matching with them, or on the cheap you can use the 69-up 351 Windsor cast iron manifolds and do the same, and make a little adjustment in your H-pipe for fit.
 

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Discussion Starter · #15 ·
The heads have already been rebuilt or I would consider upgrading to bigger valves.
Great suggestions on parts, feeling like I have some direction with this engine build now.
 

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Discussion Starter · #17 · (Edited)
Finally getting this engine put back together and am wondering about the press in rocker studs and if they are strong enough for this application. What's the consensus on this and at when are screw in rocker studs recommended?
 
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