302 rebuild horsepower

[mcdobson]

Snicker. The 289 2V had a peak torque of 288 ft-lbs ..at 2400 RPM. The '68 302-2V torque peaked at 300 ft-lbs at ..wait for it..2600 RPM. LOL..you could argue that the 289 had the cam more suitable to the Bronco. ;D

Better read up the old Ford engines a wee bit more. You are correct though..you sure do not want an engine that makes its HP at 6000 RPM. Probably why Ford never built a production engine that did..even the infamous Boss 302, their highest winding production engine, peaked at 5800 RPM.;D

Snicker and lol all you want, but why would a person building an engine revert to 40 year old specs when he can build a motor with more modern pieces and get much better performance? He did not say he was going to build a stock 302. Maybe you should read a modern performance book or get some practical experience.

 

[broncnaz]

You obivously dont know BMC69's background.%) That 40 year old technology was pretty much unchanged for 40 years and the newer technology usually raised the peak torque RPM's although HP RPM's tended to be slightly lower but torque is what moves you not HP. 40 year old technology really hasnt changed that much. even if you get a newer 5.0 engine its still all based on that orginal 40 year old technology.
1990's era 5.0's put out 210 at 4200 rpm and 275 ft lbs at 3000 rpm vs the older technology that put out 205 at 4600 but 300 ft lbs at 2600 no real big differance.
Again base model 289 specs are fine its the HiPo specs you dont really want in a bronco.

 

[mcdobson]

You obivously dont know BMC69's background.%) That 40 year old technology was pretty much unchanged for 40 years and the newer technology usually raised the peak torque RPM's although HP RPM's tended to be slightly lower but torque is what moves you not HP. 40 year old technology really hasnt changed that much. even if you get a newer 5.0 engine its still all based on that orginal 40 year old technology.
1990's era 5.0's put out 210 at 4200 rpm and 275 ft lbs at 3000 rpm vs the older technology that put out 205 at 4600 but 300 ft lbs at 2600 no real big differance.
Again base model 289 specs are fine its the HiPo specs you dont really want in a bronco.

And he doesn't know mine. But you are both missing the point. The 289 is a great motor and can move the Bronco just fine, but the op is going to build a new motor. With modern pieces from the aftermarket he can build a much better motor for his Bronco than a stock 289. That was my point. I hope I've made my it more clearly.

 

[Ranchtruck]

Comparing specs between different eras is pointless, as the specs were come up with all sorts of different ways. Take my 76 cadillac 500 for example, rated at 190hp at the time, put it on an engine dyno and it puts out 375hp stock, but 30 years later. I doubt it gained 185hp just by being used. So, now that that's out of the picture, here's a good way to make decent power:

Take your 302, find some 96-97.5 ford explorer heads (GT40 with 3 bars on the end of the head), do a little bit of primitive port work on the exhaust. Bore the block 30 over, and put flat top pistons in. Use a nice RV cam, edelbrock Performer 289 4v intake, and a off-road carb of your choice (I used an autolite 4100). I also had my heads decked .020 each, but I knew the engine was going to live at high altitude, so I could get away with the high compression.

With that setup, the bronco was as fast as my 2001 supercharged 3.4l tacoma, up at 5k feet altitude. So as far as horsepower is concerned, mid 200's. Easily pulled the bronco up to 110mph with the 3spd and 4.11's. 31" tires, stock height. It was great to drive on the highways, you could just drop left and punch it on any hill and pass people.

 

[dax]

Thanks guys! Interesting conversation. I'm learning a lot.

 

[broncnaz]

And he doesn't know mine. But you are both missing the point. The 289 is a great motor and can move the Bronco just fine, but the op is going to build a new motor. With modern pieces from the aftermarket he can build a much better motor for his Bronco than a stock 289. That was my point. I hope I've made my it more clearly.

Your orginal point was that a stock 289 makes its power at 6000 rpm which is just not true. Our point is that you can build 200 hp using similar specs to the base 289 or early 302 engines. And yes modern parts are better as things have been learned but still most of whats been learned only ups the powerband. We are talking about a relatively mild engine which is more in line with stock 289 specs. doesnt have to be exact just similar I doubt you could even get a cam with actual early 289 specs as most have all been changed slightly due to the better cam profiles availible but they are still considered acceptable as stock. Nobody is saying use only early 289 parts or build a 289 to get the 200 HP number just use parts with similar specs.

 

[broncnaz]

Comparing specs between different eras is pointless, as the specs were come up with all sorts of different ways. Take my 76 cadillac 500 for example, rated at 190hp at the time, put it on an engine dyno and it puts out 375hp stock, but 30 years later. I doubt it gained 185hp just by being used. .

Not really if you know the engines and the testing then you know where the differances are. Many big block engines were under rated for insurance reasons. Common knowledge especailly in the early to mid 70's.
Many base model 289s have been dyno'd and the ratings are pretty close to factory ratings. Same goes for late model 5.0's when it comes down to it the numbers between early and late are pretty close. One of the points is that power wise over the 30 year span they are still pretty close about the only thing that has really changed is that todays engines do it a lot cleaner.

 

[mcdobson]

I would hereby like to appologise to broncaz, he obviously knows more about Ford engines than the rest of us and is not stuck in the 60's. He obviously knows how to calculate the difference between how the engine specs were rated in different decades. By all means build an engine with 289 specs. from the 60's instead of a longer stroke motor with better pistons, roller cam, aluminum heads, roller rockers etc.. I'm sure you will get much better HP and torque.

 

[broncnaz]

Apology accepted.:-*
I dont claim to know more about anything than anyone else knows. but I know what I know and I try to answer peoples questions in accordance to what they are asking. Not go off on some tanget about how you need all these aftermarket parts.
The whole point of this thread is to build a relatively stock engine with about 200 HP which IS very easy to do with specs (similar) to 289 or early 302 specs.
Aftermarket heads, roller rockers, long stroke ect are not needed to make those numbers. Had he been trying to make 300 hp or higher then yes those parts would pretty much be needed.
And as far as HP testing well from all my research pre 72 SAE gross HP numbers and 72 up Net HP numbers are not all that far from each other. IMO.
Sure Gross was usually done without accesories and might have even had headers but still accesories take maybe 10hp to run and headers would only add maybe another 10-20 more HP over a Net HP rating so you only talking about maybe 30 hp If you look at engine specs in 72 in almost every case compression went down more smog controls were added, cam profiles changed, timing sets were retarded all in effort to comply with stricter emissions standards. In effect power numbers went down. So you cant really say there was a large decrease only because of HP testing methods changed. engine specs changed as well which accounts for some of the power decrease.
I dont have anything against new aftermarket technology my 302 in my 73 sports TFS heads, Roller rockers crane cam ect. and probably puts out about 250 hp at the crank.

 

[mcdobson]

Sorry, DAX.

 

[dax]

Sorry, DAX.

I'm good. I have a steep learning curve.

 

[Ranchtruck]

Not really if you know the engines and the testing then you know where the differances are. Many big block engines were under rated for insurance reasons. Common knowledge especailly in the early to mid 70's.
Many base model 289s have been dyno'd and the ratings are pretty close to factory ratings. Same goes for late model 5.0's when it comes down to it the numbers between early and late are pretty close. One of the points is that power wise over the 30 year span they are still pretty close about the only thing that has really changed is that todays engines do it a lot cleaner.

Yes, but the point is it's a common thing for people to look at the "advertised power rating" of a certian year engine and say "wow, I want my engine to make that", when in reality the "advertised power" was a fictional number. Building a motor to 1967 specs may not net you the "advertised power" in todays measured horsepower.

The shortblock hasn't changed in 50 years, but the heads have. A stock GT40p head from an explorer will do a lot better than a stock 68 bronco 289 head will, not just in high rpm, but all across the rpm range. Better flow patterns, better turbulance, better spark plug placement, better quench areas, all help low end power just as much as high RPM. It's not neccesarily a concrete trade off that an engine that has higher peak HP#'s has less torque in the lower RPMs where it's needed for offroading. So, you can have a better engine using stock, latest generation parts, than you would if you redid the heads on your 1960's engine, and not loose anything in the low end.

 

[broncnaz]

Funny thing is that standards have changed again and usually the engines put out more than the factory rated them at. But I agree the advertised HP ratings tend to be on the higher side for a lot of early(pre72) vehicles. Anything that is marketed uses the highest numbers possible as numbers sell but they were still fairly close to the advertised so called fictional number.
I also agree there are some late model parts that are better than old 289/302 heads thats bound to happen if they couldnt improve anything over the course of 30 years then something would be worng. GT40 P heads are better than bone stock early heads although I would go with standard gt40 heads any day over the P heads just because of the header/spark plug clearance issues P heads have. theres a minimal HP differance but if the price is right then they are a nice factory power adder.

 

[dax]

So can you find gt40 heads at a junk yard? Get them used or rebuilt? Swap meet? What vehicles had the gt40 heads that I could use for a 302?

 

[Broncobowsher]

The GT40 heads that are easiest to find at a junkyard are those off a '96 Explorer 5.0
They are the 3-bar heads. 4-bar are the P heads and they can be a Pain. Spark plug angles changed and usually there are interference issues with the exhaust. The manifold off the Explorer clear the plugs but not the Bronco chassis, so that isn't a fix either.

The heads wee also used on some Cobra engines and 5.8 lightening engines. But those a premium performacne engines and the Cobra and Lightening names attached tend to drive the price excessivly high for the name plate more then the function.

 

[JDJ]

Dax,

I don't know if you would be interested....but I have a '93 ford F350 work van (complete). It has a EFI 351w and an automatic tranny. I don't know how much you are looking to spend or if you ever want to add EFI or not....but I am thinking about selling the van. It is complete and it runs.

I'm only about 2-2.5 hrs from you. PM me if interested.