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1968 Go Fast Parts

p51

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Just thinkin'....

My car is a pretty much stock 302 J-code with stock manifolds, dual exhaust, 10.1 compression, T5, 3.4 rear end with an Edelbrock 1406 carb. It puts out max 230HP @the flywheel and ~195HP (dyno'ed) to the wheels. I get just over 20mpg w/80% highway driving and "grandma'ing it" when accelerating on the 20% of street driving.

What I'd like to do is get 300HP max HP at the wheels but still get the 20+ mpg with the 80% highway driving profile. I'm thinking:

(1) Adding EFI (FiTech) will get me ~10% to 15% kicker in MPG. This is roughly what I saw previously when I put on (and subsequently took off) aftermarket EFI.

(2) Tri-y headers replacing stock manifolds should get me some free HP at the same MPG

(3) Adding a top-end Edelbrock kit such as 2027...
"E-Street for 289-302 S/B Ford (1981 & earlier) - 321 hp & 337 ft-lbs.
Performance results obtained on a 302 Ford short block with 9.1:1 compression."
http://www.edelbrock.com/automotive/mc/power-packages/top-end-kits.shtml
Clearly this will add performance but reduce economy.

The goal really is more spirited driving not necessarily speed...

The German/engineer in me is wanting to get to 300HP/20MPG w/EFI. The Scot in me wants this to be as cheap... er frugal... as possible... :wink:

Just a "what-if" experiment at this point... but I was wondering whether you guys thought it was possible to do 300HP/20MPG on the setup I already have plus the mods described. Or how would you suggest I go about doing this?

Note: I'm really not planning to do this anytime soon... just like thinking about it... and I do enjoy that the "thinking about it" is *free*... :grin:
 

dalorzo_f

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Well... as the "300 Hp" would be a top-of-the-curve point at high rpm. And on the street... with some effort to get your mpg goal... you would see that point about 0.3271% of the time you drive... if you keep your foot out of it I'd see no reason why you can't get at or close to both.

But would say 300 at the flywheel would seem more realistic than at the rear wheels if the 20 mpg is a goal. (assuming 15-20% for a manual parasitic losses you're talking near 350-375 flywheel for 300 rwhp, which is getting into big Hp for a "mild/economy" build 302)

If you floor it all day long, not likely to hit the mileage goal.
 

rvrtrash

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Personal opinion only, but to get the type of HP you're looking for, using conventional means, you'll dump your MPG down a hole. You can pick up some "free" hp with the headers, and a little if you go to a roller cam, but you'll need to move more air/fuel through the motor, which means a more radical cam, higher compression, bigger carb, stuff like that, that will kill gas mileage, even at low rpm. My 302 was about 275 hp at the crank, with stock heads, 9.5:1 compression, holley intake and 600 carb, tri-y headers and a comp cams "medium" camshaft. I got about 15 mpg, just cruising around in town. With that said, deep down in the darkest recesses of my twisted mind is a nagging idea to someday pick up a pair of small, cheap turbos, like the ricer crowd puts on their Honda 4 bangers and build a twin turbo Ford small block on the cheap, with a late model 5.0 fuel injected, roller motor. HP when the pedal is on the floor and gas mileage when I'm driving mama to the store. Just something to think about.

Steve
 

Mosesatm

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Before creating a lot of power you may want to make sure the T5 can handle it. My J-code put out only 200hp but 300 torques. If I remember correctly the T5 is rated to around 300 ft#.
 
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p51

p51

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Thanks for the inputs. Yeah, I'm guessing it's a real pipe dream. Maybe a 230RWHP/20MPG highway might be doable w/5-speed + tri-y's + efi + better intake...

Good point about the T5 torque spec which just about matches what a stock J-code engine puts out at the crank.

Hmmm... maybe a 3.5L EcoBoost... :wink:
 

robert campbell

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All of the above is good information. I bet the T5 will last as long as you do not add big tires and hammer on it a lot.

The heart of power is compression. You 302 J code is rated at 10.5 to one with its small 53 CC combustion chamber heads. Any head with a 60 CC combustion chamber will lose some power due to less compression. Certainly the Edlebrock heads with 60 CC chambers make up for the loss by better flow larger valves when combined with a more aggressive cam plus long tube headers.

Todays gas not working well in higher compression vintage engines is a lot of baloney. It is all about the combination of parts and proper tuning. I am running a 13 to 1 289 in Val's Fastback on 92 gas. It would make more power if Neil would share his aviation fuel and have to be totally retuned to use it.

The below link is to a 56 CC head that will retain your compression better.

https://www.summitracing.com/parts/tfs-52515601-c01/overview/make/ford

A Comp Cams "Extreme Energy" flat tappet cam will retain good engine vacuum while utilizing the heads for all they are worth. I have used the below cam in J Code 302 engine builds. Works good with stock heads, but really shines with better heads. As all Ford small blocks do. And will work great with a 600 CFM carb or better with FiTech fuel injection.

https://www.summitracing.com/parts/cca-31-242-3/overview/make/ford

Long tube headers? This is the best choice for fitment power and ground clearance. And competitively priced. Must use a later Ford 302 small starter.

http://www.fordpowertrain.com/fpaindex/Mustang1.htm

Pic of the ground clearance and the 3 inch exhaust on Val's Fastback. I have the same on my GNS.



 
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p51

p51

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Rob, thanks for the info/insight... I am already starting to feel my wallet getting lighter :wink:


...Todays gas not working well in higher compression vintage engines is a lot of baloney. It is all about the combination of parts and proper tuning. I am running a 13 to 1 289 in Val's Fastback on 92 gas...

Per your comment above. I've also never had any issue with 92 gas with 10.1 compression (at one point I thought I did but it turned out that what I thought was knock was a resonance vibration).

One question/comment on the 13:1 with pump gas. I'm guessing you're running a pretty radical cam on that which would mean that there is a lot of overlap in the valve timing (?). Wouldn't that drop the dynamic compression over a stock cam sorta giving the 13:1 static compression ratio a much lower "effective compression ratio"?
 

robert campbell

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Rob, thanks for the info/insight... I am already starting to feel my wallet getting lighter :wink:




Per your comment above. I've also never had any issue with 92 gas with 10.1 compression (at one point I thought I did but it turned out that what I thought was knock was a resonance vibration).

One question/comment on the 13:1 with pump gas. I'm guessing you're running a pretty radical cam on that which would mean that there is a lot of overlap in the valve timing (?). Wouldn't that drop the dynamic compression over a stock cam sorta giving the 13:1 static compression ratio a much lower "effective compression ratio"?

You are right on! It is a monster .600 lift solid roller and it absolutely bleeds off static compression at low RPM's. Which assists in the detonation arena. The solid roller quick lobe ramps allow for huge duration and a bit less overlap, but all in all it works great. 18 degrees of initial and 38 total on in with no vacuum advance Mallory Unilight. Solid rollers have a "lazy" sounding idle that is far different than a large flat tappet cam. I idle it at around 1,000 RPM and with the Webers it has a huge power curve. From idle right on up to 7,500 RPM. It was a special grind from Cam Techniques who grinds for Inglese and NASCAR guys. To match all aspects of my build. Car weight, intended use, rear end ratio, trans choice, engine deck height, blah blah blah.

I told him I wanted a grind that would make this engine all it could be from 1,000 to 7,500 RPM. It does just that!!

On a compression note a local guy built a 9.0 to 1, 390 for a 1975 Hi Boy Ford 4X4 truck with an automatic. Put in a mild cam that destroyed the vacuum and the combination is a bit of a stone. No compression, no power!

Rob
 
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p51

p51

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...18 degrees of initial and 38 total on in with no vacuum advance Mallory Unilight...

Dang! 18 degrees initial. That's impressive. Question, do you know at what RPM you hit you "all in" 38 degree BTDC advance?

I've got an "all in" of 37 degrees but I only hit it at ~3400RPM. I'm wondering if a faster ramp might get me a bit more "giddy up"...
 

robert campbell

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All in at 3,000 RPM. I would say you are spot on with your setup. One of the tougher cars in stock form for pinging is the 1968 J code. As I push the initial forward with the small cam profile they have little bleed off of compression at low RPM's. They get what I call light throttle pinging going up a hill. Also due to frugal (lean) characteristics of the 4300 4 barrel. These carbs were Ford's first adventure into emission control.

The vacuum advance is nearly all in due to the great vacuum signal of these high compression small port engines at highway speeds on the flat. As you pull the hill under light throttle the vacuum advance is applying to much advance if you have the initial timing at 12 or more degrees. Floor it, engine is now at 0 vacuum, and the pinging stops.

What I do with the newer NAPA style single style diaphragm is to adjust it. Many of the newer diaphragms are adjustable with a small allyn wrench. I turn the adjuster in counter clockwise which shortens the curve and delays when it is all in. This allows for the initial to stay in the 10 to 12 degree range.

All that said if the engine is totally stock the stock specs are just fine. I have found that bumping stock engines a bit forward seems to be just fine.

They above is geared more to engines with a mild cam and maybe a pair of HIPO manifolds or headers. The more the mods the more the owner is searching for a bit more "kick" in their pony. That is when I really start to deviate from stock to get the most out of it. And in the search for kick, the owner gets the best gas mileage and they run a bit cooler.

At some point in the engine build I take the vacuum advance out of the equation and upgrade to a non-vacuum advance adjustable curve distributor.

Rob

With
 
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p51

p51

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All in at 3,000 RPM. I would say you are spot on with your setup...

...The vacuum advance is nearly all in due to the great vacuum signal of these high compression small port engines at highway speeds on the flat....

...What I do with the newer NAPA style single style diaphragm is to adjust it. Many of the newer diaphragms are adjustable with a small allyn wrench.

Rob

Thanks for the input/advice. Always appreciate it.

You're right about the good vacuum on the stock J-code... I get ~17" vacuum at idle.

I've got one of the adjustable vacuum advance canisters. I'm not clear if the adjustment changes:
(1) The point where the vacuum advance starts dropping out as you open the throttle (and the vacuum begins to drop)...
(2) Or limits how much total vacuum advance you get (I know its ~15* max)

I think it's #2 but I've read comments on the web that imply both. I probably just need to get under the hood a futz around with it to see.

Thanks again,
James
 

robert campbell

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James,
I cut one in half down the middle. It limits how much and when it starts to pull in via a large spring. Of course based on the vacuum signal of the engine. A J Code pulls a lot of vacuum so it takes more "turns" in to affect it.

If you buy one from NAPA it comes with an instruction sheet on how many turns from fully turned out clockwise for various Ford engines. 390's, 351's and such. X amount of turns Counter clock wise for various years and engines.

But with cams and other add ons you need to fine tune yourself.

Rob
 
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p51

p51

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James,
I cut one in half down the middle. It limits how much and when it starts to pull in via a large spring...

Rob

Well now, that explains it, the adjustment does a little of both #1 and #2 - when you adjust away from max it not only reduces the total degrees of advance but increases the vacuum point where the advance is engaged. The discussion on some of the forums goes back and forth on this...

Thanks!
James
 

robert campbell

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James,
You got it right on. It does both. Ford used to accomplish this with spacers, shims, and springs of different length and tension. The same vacuum advance diaphragm was used on basically all their V8 engines. Each engine family and HP rating had different components to adjust how much and when.

I have a small jar of these shims and such for the old Ford diaphragm and can perform some tweaks on them also. The old Ford diaphragm is very hard to find and most have failed and have been replaced.

I just had a radical 454 Chevy in my garage to tune. 750 CFM carb and the primary's were so far open that the ported vacuum port was drawing vacuum at idle in park. Terrible manifold vacuum at about 6 inches hot idle at 1,000 RPM. The adjustable vacuum advance was all the way loose and it was drawing in around 10 inches of advance even on the ported connection at idle. Drop it in gear and the stock converter brought it down to 600 RPM and zero manifold vacuum. The engine lost 10 degrees of advance and would blubber all over itself and die. Power valve was a 6.5 so it was all in at idle. Gassing you out of my garage!! Driving it resulted in a loss of 10 degrees of timing as you pulled away from a light causing a noticeable hesitation.

A cracked the secondary stop screw 1.5 turns to close the primary. Dialed in another 10 degrees of initial and turned the vacuum advance in 2 turns to slow it a bit. Dropped the power valve to 2.5 inches.

Result was 9 inches of vacuum at idle and around 2 to 3 at idle. Far less "gassing" and my eyes quit burning. Cam still hates 600 RPM in gear and his only choice is manual gears or a stall converter.

I love to tune!!!

Rob
 
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p51

p51

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I just had a radical 454 Chevy in my garage to tune. 750 CFM carb and the primary's were so far open that the ported vacuum port was drawing vacuum at idle in park...

Very interesting... I must be starting to actually understand this stuff, I followed that whole line of argument. Gotta give myself an atta-boy :wink:

Thanks again
 

robert campbell

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I have cured the woes of many a radical cam engine by cracking the secondary's. Just did a 289 4 speed Mustang with the same problem. Owner was running a basically stock motor with a 4100 Autolight 4 barrel. The 4100 has an adjustable secondary stop. His air screws were ineffective due to the primaries off the transfer slots. Bad idle, hesitations, and burning eyes.

Crack the secondary's a hair and dial the front back in. Runs perfect!!

By the way, you already got this stuff, but it is fun to bench tune with people!!

Rob
 
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p51

p51

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I have cured the woes of many a radical cam engine by cracking the secondary's...

Now that is a neat idea... I think it would've taken me a while to come up with that one.

I'm sensing that there is an EFI build sometime in your near future - on the threads I've read one of the advantages for radical cam cars is it smooths out the idle, I suppose because of the IAC (caveat: EFI evidently needs some amount of vacuum signal to learn so if the cam is too rad getting the EFI to self-learn is an issue). If you ever do go the EFI route let me know. I've had EFI (PJIII) on and off my car and I have some definite ideas of what and what not to do...
 

robert campbell

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I toyed with the idea of a PJIII. To much dough. I talked to FiTech and they said they will have an 8 stack in the next 6 months for a lot less than the others out there.

I think FiTech is really going to have an impact on the market for vintage cars and EFI.

Carburation dinosaurs will soon fade into the tar pits..... But not yet!!! And working with a FiTech base system would be fun to figure out.

Rob
 
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p51

p51

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James,
I cut one in half down the middle. It limits how much and when it starts to pull in via a large spring. Of course based on the vacuum signal of the engine. A J Code pulls a lot of vacuum so it takes more "turns" in to affect it...

All this discussion got me wondering just where the vacuum advance curve was set on my distributor. Got out the timing gun. Hooked a MityVac handheld vacuum pump to the distributor vacuum advance canister. Started the car and added vacuum to the vacuum advance canister in increments. What I found:

@6" of vacuum the advance starts to kick in
@16" of vacuum the advance maxes out at 15*
The degree advance seems pretty linear with vacuum increase most of the way
 

robert campbell

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James,
Back from the lake cabin!!!! So so weather, but lot of fun.

So at hot idle you have all the vacuum advance in. I think you said you have 12 degrees of initial lead? So at idle you are at 28 degrees of advance. Sounds like a lot of advance!!! But it does not come in until the engine starts so your starter must be happy.

You and I have been here before. So if you leave a light at moderate acceleration, your engine immediately loses from 6 to 16 degrees of advance until the centrifugal spins in. Same can happen with ported vacuum, but you can dial in more initial advance to compensate.

Boy are we pickin in the weeds now! If you had any flat spots I would tell you to experiment with ported vacuum, more initial timing, and restrict the vacuum advance. But you say none of that exists and the only way to tell would be a dyno and a vacuum gauge to see which combination produces the best off idle power gain. and you would need to install a throttle stop to ensure each run was equally opened to the same spot.

This is such cool stuff! Hope we are not boring the rest of the site!!

Rob
 
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