Step by step hp increase?

[66 Bronco]

Hello.

My name is Hjörleifur, and I live in Iceland.

I have been runnin a '80 200 in my '66 Bronco for years and loving it. I've got a brand new 2 bbl on it with the clifford adaptor, some nice long headers and the duramax distr. Other than that, bone stock. The 2bbl and the headers made a nice diffrence, however I was hoping that you good people could give us less knowing the, say, top five or six things to do and perhaps parts needed to increase the hp but hold a deascent mileage? I've ran a few search in the forum but not found "the idiots guide to increased hp"...

Thanks alot for a brilliant forum and great tips.

Hjörleifur.

 

[Eric Rose]

You mean a duraspark distributor. A Duramax is a GM diesel engine and, therefore, has no distributor.

Once you've got an electronic ignition, a header, and a 2v carb, the rest of your power gains will probably be found inside the motor, and in the gearing/drivetrain.

On an '80 motor the most obvious thing you can do would be raise the compression. On the later motors, the piston crowns sit about .025" down in the block, so the best way to raise compression is to mill the block for zero deck height.

The easiest way to raise compression would be to mill the head though, as that would require less work taking than taking the motor out and disassembling it, etc. Either way you should be able to get it up to 9:1 or higher.

You can probably pick up some power by direct-mounting the carb to the log instead of using an adapter, and smoothing the ports, un-shrouding the valves, etc.

You've also got potential for mileage/accelertaion gains in your choice of gearing. You can do things with gear ratios and adding overdrive that will help you make the most out of the power you already have. Not sure about how you'd add overdrive on a 4x4 Bronco, but its worth looking into.

 

[66 Bronco]

Thanks for the reply, I hadn't thought of compression yet. I was looking at our pick up out the window and wrote Duramax.. Anyway. I am well aware of gear ratios and set ups in that department, been a 4x4 geek all my life.

After milling the head as much as possible, or even the block, porting and lowering the carb, how about a better cam to get some more flow? Does that require bigger valves?

H

 

[Explorer]

The Classic Inlines site, host of this forum, has a step by step guide. Plus the Ford Falcon Performance handbook will help you.

 

[Eric Rose]

Yeah, a better cam will help out. The stock cams are pretty conservative, so there are good gains to be had with a cam. You'll want to have it degree'd when you install it.

You won't need bigger valves, the '80 head has the biggest valves that Ford put into these motors anyway. You can get bigger valves if you'd like... but with the log head and the little 1v carb hole they might not benefit you that much.

Really the log is the biggest restriction, and there are ways to get around it...

direct mount 2v
Offy tri-power (three 1v carbs)
Aussie 2v head
Classic Inlines aluminum head

 

[66 Bronco]

Explorer, thanks, been reading all night.


Eric, this is good to know on the valves. Should have done my homework last winter before I pulled of the log. Thank you for the info, carb closer to the intake and a cam are on the wishlist.

Hjörleifur.

 

[CZLN6]

Howdy H:

And welcome to the forum. You didn't say which carb you are using? I'm guessing you already have discovered the value of increasing the initial advance setting with this engine. Even at sea level a setting of 10 to 12 degrees before top dead center is reasonable.

Are you planning a complete engine build/rebuild this winter. There is another gentleman there that really got into his 200(s). He hasn't posted in awhile. I'll see if I can find his call name. After carb, header, ignition and exhaust, the next steps will be a performance head/valve job with an increase in CR. Add to that an appropriate cam and cam gear and your Broncho will be jumping over those glaciers you got there.

Adios, David

 

[colocounty4]

Hi,

10 to 12 BTDC at sea level? Yikes. I'm at 6000 and I run 14 BTDC. I've never tried any higher. You don't think that's too conservative, do you?

 

[66 Bronco]

Sæll David!

I'm running a brand new 350 cfm Holley, I rebuilt one a few years ago and used it for a couple of years but was never really happy with it. The new one is briliant, 350 might be stretching it a bit but it runs good anyway. I am running it at 6 degrees before TDC, think I should go for 10?

Thanks, Hjörleifur.

 

[CZLN6]

Howdy Back:

Hey both H and ColoCo4- Finding the right/best setting for your initial advance is,very much a try-and-listen process. Many factors effect the "Best" setting. Elevation is one. Others are ambient and engine temperature, humidity, A/F ratio, compression, quality of gas used, type of transmission, and others. The way to proceed is to start with a basic tune-up so that the engine is running at its best. Begin with a stock setting plus 2 more degrees. Then drive the car normally for a week or so, listening carefully for any pinging or knocking. If you get any knock, re-evaluate your basic set up. There should not be any. So, assuming all is well, Reset the initial with 2 more degrees of advance and evaluate again. At this point, evaluation includes listening and checking the spark plugs. Repeat this process until you hear pinging then back down the setting until all is quiet. Try to eliminate gas quality and octane rating by always using the same brand and octane rating. Be aware that hotter, summer temperatures and/or lugging the engine can cause cylinder temperature spikes. For that reason, I like running a one step colder spark plug heat range in the summer.

If your spark plugs are white and chalky, glazed or showing signs of peppering you are either advanced too far, too lean in A/F, or too high engine temperature.

H- your '80 engine is rated at 8:1 CR and your Holley 350 is probably on the rich side, so 10 to 12 degrees of initial will not be too much. I'm also guessing that Iceland climate will be cool and humid?? If so, those conditions will lend themselves to a little more advance.

ColoCo4- I don't remember the details on you engine and car, but trying 2 more degrees won't cost a thing and may be worth some additional mileage and power.

Be aware that there is a point of diminishing returns. At some point, more initial advance will only generate more engine heat. So, once you find your engines advance limit, begin backing off of the limit looking for a loss in MPG and/or power. The goal is to use the least amount of initial advance to achieve the most power and mileage.

H- I love Holleys! They are so tuneable and, therefore, so forgiving. Moving away from the adapter and modifying the log for a direct mount will be a noticeable improvement with this carb. There is more carb there then your engine can use right now, but the OEM one barrel wouldn't allow your engine to utilize all of it's potential. I think your are way better off with the 350 for now, and there's more potential for the future.

Adios, David

 

[66 Bronco]

Thank's a lot David!

This is priceless info, I can't wait to put it in the garage and start fiddling..

You got to love this forum!

H