Aftermarket EFI installation - Questions

Rusty_S85 wrote

You should be fine either way.  It sounds like yours is pretty mild build I dont know how much milder you could go without it be a stock engine.  I think my build is a bit higher up on the mild scale, yours sounds like its basically a stock 302 just with a Comp Cam thrown in.

Well it did go from 135HP to 300HP, and around 250 torque to 335 torque, so there were some nice gains there. Unfortunately, the gains with the 302 are mostly in the 3000-6000RPM range, and I spend all my time between 1500-2500RPM. Knowing what I know now, I probably would have left it mostly stock. It would serve my purpose better that way. Anyway, we'll see how she works with the new smaller carb installed. It will be a couple weeks, but I'll report back on it when I do.

Rembrant wrote

Rusty_S85 wrote

You should be fine either way.  It sounds like yours is pretty mild build I dont know how much milder you could go without it be a stock engine.  I think my build is a bit higher up on the mild scale, yours sounds like its basically a stock 302 just with a Comp Cam thrown in.

Well it did go from 135HP to 300HP, and around 250 torque to 335 torque, so there were some nice gains there. Unfortunately, the gains with the 302 are mostly in the 3000-6000RPM range, and I spend all my time between 1500-2500RPM. Knowing what I know now, I probably would have left it mostly stock. It would serve my purpose better that way. Anyway, we'll see how she works with the new smaller carb installed. It will be a couple weeks, but I'll report back on it when I do.

For comparison, Lucille went from 133 to roughly 275 HP, but torque went from 233 to 340 ft/lbs. at 2000 RPM (360 peak at 3500 RPM).  But I have heads with smaller combustion chambers and valves, and a milder cam.  It's weird how that works, isn't it?

The smaller carburetor is a better match for your engine size, but I am not sure how much of an improvement you will see from a performance standpoint with your head and cam selection.  The fact is your heads were designed for a bigger engine, and your cam is designed for higher RPM use.  I really think you need lower (higher numerically) axle gears to get your truck into it's power band quicker.  

I recently changed gears on my 1998 Jeep Wrangler.  It has a 4.0 straight six and came stock with 3.07 gears with a 3-speed automatic.  When I got 31" tires, the problem became even worse.  Swapping to 4.10 gears made all the difference in the world.  My Jeep is more responsive everywhere, and low end torque went from abysmal to outstanding!

LARIAT 85 wrote

The smaller carburetor is a better match for your engine size, but I am not sure how much of an improvement you will see from a performance standpoint with your head and cam selection.  The fact is your heads were designed for a bigger engine, and your cam is designed for higher RPM use.  I really think you need lower (higher numerically) axle gears to get your truck into it's power band quicker.  

Yeah, the GT40 heads were used on the first gen Lightnings with 351's, the Mustang Cobras, and the very early Exlporer's with 5.0's (that's where mine came from), before they switched to the GT40P heads. I hear people say that the GT40P heads are the best SBF heads Ford ever made, but because of those funky spark plug angles, they're a pain to use/install. They're also much smaller CC's, like the E7's.

I love my little 302 and have no regrets building it how I did. It works pretty darn good for what it is, and routinely returns 18mpg. I get lots of compliments on how it sounds. However, like everything else, I have had my fill of it, and I'm wanting something a little milder now, so I'm thinking about building a mild-almost-stock roller block for it, with a focus on having it run as smoothly as possible (like stock). Have everything balanced, even the pressure plate and flywheel, etc. Along with that I would probably install some quieter mufflers as well as soundproof the cab a little better.

I love the mild idle and hotrod feel/sound of the engine, and like I said, people love it, but I drive the truck A LOT. Last wekend I put 300 miles on it. The weekend before, 200 miles. Going across town to the local weekly car meet is one thing, but actually traveling with the truck is a whole other experience.

So the plan for this winter (tentatively) is to make the truck nicer to drive (smoother, quieter, etc).

I've thought about re-gearing, quite a bit actually. I think most guys would ditch the 3.08 diff with my set-up, but I quite like it like that...maybe a set of 3.27's or whatever is between 3.08 and 3.55's. The truck hums along really nicely at 2000RPM and 70MPH, but with a bare steel cab and floor, with no AC, loud exhaust, and a mild engine that vibrates through the truck LOL, it's better suited for the younger fellas.

Anyway, stay tuned. I need to research my cam selection again and plan a bit for what I'm going to do with this thing.

Rembrant wrote

Rusty_S85 wrote

You should be fine either way.  It sounds like yours is pretty mild build I dont know how much milder you could go without it be a stock engine.  I think my build is a bit higher up on the mild scale, yours sounds like its basically a stock 302 just with a Comp Cam thrown in.

Well it did go from 135HP to 300HP, and around 250 torque to 335 torque, so there were some nice gains there. Unfortunately, the gains with the 302 are mostly in the 3000-6000RPM range, and I spend all my time between 1500-2500RPM. Knowing what I know now, I probably would have left it mostly stock. It would serve my purpose better that way. Anyway, we'll see how she works with the new smaller carb installed. It will be a couple weeks, but I'll report back on it when I do.

Good gain still for how little you did.

For my 302 im going from the stock 125hp/250trq (1982 figures I found online) to what DD2000 is estimating for me of 404hp @ 5,500 and 407 torque at 4,000 - 4,500.  I think I will be more or less around 375 hp but have more goodies than the blueprint 306 crate engine they dyno out at 380hp.

I figure should pull good cause if I am cruising on the highway between 2,400 - 3,000 rpm I will be cruising at 379-389 trq and when I nail the throttle it will go up to 407 and finally 385 at 5,500.  In my case low and midrange is what I am shooting for and that is where most of the gains are at for me.

For yours with such a low rpm range you are at on the highway having most gains in the 3,000 plus range is a bit outside of your use.

Depending on how accurate my DD2000 is which I find is fairly accurate if you put accurate information in it tells me the following.

2000 rpm / 139 hp / 365 trq
2500 rpm / 180 hp / 379 trq
3000 rpm / 222 hp / 389 trq
3500 rpm / 266 hp / 399 trq
4000 rpm / 310 hp / 407 trq
4500 rpm / 349 hp / 407 trq
5000 rpm / 381 hp / 400 trq
5500 rpm / 404 hp / 385 trq
6000 rpm / 409 hp / 358 trq

For you, I suspect your cam is the biggest contributor for your power gains being in the higher rpm range.  I noticed with comp they love to use single pattern grinds while Crane who I went with uses a dual pattern cam with exhaust having more duration to help offset the restriction of OE heads on the exhaust side.

On your axle aspect I am changing mine, OE was 2.75:1 but with the 31x10.50-15 KO2 tires it kills the low end.  I am actually shooting for 3.25:1 which would make my overall ratio 2.90:1 with my taller tires.  To off set this and help the low end I am having a E4OD planetary gearset installed in my C6 on rebuild to get a lower first and second gear to help with acceleration to try and offset the taller tires.