Assuming 1.5 rockers, which is "better" for city driving fuel economy wise? How do they compare on the highway speed/rpm/mpg wise? This is going to be with TFS-30300006 heads with a q-jet and a Performer RPM intake manifold, most likely. I'm leaning towards the 464, but would like to see others' opinions.

 

It would be a dog. The heads and intake are okay for each other, but either cam would be a total mismatch.

You either need more cam, or less intake/heads.

 

A dog as far as what? How would the acceleration to regular highway speeds be, say 60-65? I don't think I'll ever pass 5k RPM. Can you give me an idea on some heads that would better suit the cam while supporting .540" lift without work on the heads? I don't want more cam because that'll equate to less mpg as far as I know..

Edit: Nevermind the suggestions on heads/intake, I'll look around.. but I'd still like to know why it'd be a dog.

 

yeah kid, how about it? (btw, five7kid is no spring chicken, he usually knows his stuff as well as anyone) I've built such combinations, my customers have no complaints. First, how many cubic inches are we talking? If it's a 350, you'll need some seriously dished pistons, but otherwise it still looks fine. What you're looking at, if you put these heads and the 407 cam to a 350 is not much different from having a RamJet 350 but with the 50 pound weight advantage of aluminum heads. Sure, these heads would take well to a bit more cam, but it's not necessary. With either of these cams, you'll need to stay under 10:1 with aluminum heads. The 464 cam would be more powerful, but the 407 will do much better below 1500 rpm. Make that 2000 if you're thinking 305 instead of 350.

 

yeah, it'll be in the 305. I'm thinking of sticking with the stock heads if the #s are right (can't think of the casting # right now, just woke up to finding out about a job interview tomorrow at 7am.), if not then I'll go with the new heads.

 

The large (relatively) ports will reduce intake velocity, leading to poor low-RPM torque. The cam will run out of breath before the intake and heads get going. It's the worst of both worlds, and even worse on a 305 (and I assumed you were talking about a 350).

The Ram Jet has standard Vortec heads, which have smaller ports than these 175's. And, it's a 350, not a 305.

If city driving and fuel economy are your goals, upgrade the cam, upgrade the intake to a Performer (not RPM), and free up the exhaust. You shouldn't have to do anything with the heads, although some port clean-up may help.

 

First, those heads first listed are 175cc, while the Vortecs used in the RamJet 350 are 170cc, not enough of a difference to feel. Second, I've owned and daily driven a 305 with 190cc heads and a 2000-stall converter, there is no problem there. Maybe not ideal, but it feels acceptable to drive, even for non-car people such as my then-girlfriend. Fir city driving and fuel economy, a 2000 stall feels great, while a 2400 stall is maddening. Unless you're running 3.73:1 gears, in which case mileage is going to suffer anyway. So, choose your heads and converter and axle ratio, then we'll discuss cams.

 

Let's put it this way - you need to make decisions in this order:

1) Usage (meaning, prioritize what you want out of it)

2) Engine size to accomplish #1

3) Heads, cam and intake to accomplish #1 given #2

It is possible to get satisfactory results with less than optimized combinations. What you usually end up doing in those cases is spending money that didn't advance your goals.

FWIW, my DD has 2500 stall - not enough for the track, but by no means too much for the street (actually very nicely balanced for the street). 1152 mile round trip to Topeka Heartland Park last month, 5 passes down the 1320, averaged 23.0 MPG for the trip (including those 5 passes).

 

Yes, and my '95 Z28 convertible got 22 mpg at 85 mph across wyoming with the converter unlocked, but it was still real annoying when I wasmoving away from a stop and not wanting to blaze the hoops. The more rear gear you use, the more stall speed you should use. Aside from the converter issue, I do agree with kid about the rest of his last post.

 

Unfair to compare! I'm talking a lame ol' computer controlled carb, not Gen II EFI. . .

A converter that lets the engine get into its powerband, regardless of the situation (street, track, etc.), really makes a car feel "right". The 4000 stall converter in the '57 feels just fine on the street (although the car isn't at all built for street-friendliness).

Gear choice is a function of whether you're building for track or highway.

 

The EFI has nothing to do with whether or not a 2400 stall is too loose. In fact, with a properly calibrated QJ on GM's carbureted LT1 intake, this engine woulda made even more torque at 2400 rpm, due to the longer intake runners of that intake manifold. But Noone Needs Anything looser than a 2400, even for at the strip, unless there's something wrong with their combo. Now, choice of axle ratio has to match the cam, and choice of converter has to match the intended use, then the cam has to match the converter. So 1 is determine the future of the car. 2 is choose displacement and converter, then 3 is determine cam, heads, compression and rear gear. But it can't always go that way as it should.

 

BTW, the loss of the lockup feature was costing me fully 5 mpg.

 

Get ready...

Sorry for the late response, been busy and did some research before posting this time , but alright, my plan is to gain low-mid range power while gaining fuel economy as well. Most of my driving is done between 1000-2000 RPM range. Obviously, performance = an increase in fuel economy, if the style of driving is kept the same. I only have $1500 or so a month to play around with so I'm trying to piece together a set and once I have everything, I'm going to spend a weekend putting it all together. Efficiency and Performance/$, it almost looks better to buy 1.94/1.50 heads with larger combustion chambers and better flow along with picking up a roots style supercharger.

1) Above
2) '87 LG4 305 stock
3) Cam- 08-464-8 because of it's low amount of overlap (32 degrees), high lift (.550/.546) (with 1.6 rockers, but I may stick with the 1.5s), and 113 LSA.
Heads- I'd like to keep the TFS I had mentioned earlier, but my CR would probably be a bit high so if those wouldn't work; I'd like heads that have a 64 CC chamber since they'd leave me at roughly 8.1 CR, whereas 68 and 72 would leave me at ~7.8 and ~7.5 respectively. As far as I know, it's better to run with a higher CR than higher boost, correct me if I'm wrong.
So now I'm stuck between the TFS-30300007 (56cc chamber), Edelbrock 608979s, Edelbrock 60979s (E-tecs), and WP 043650-1, unless there are 2.02int that will fit, but I've read that people have had problems with them and I'd rather not risk it unless it's guaranteed to work.

Lastly, the supercharger is going to be a M112 which should be more than enough for my 305. Does the supercharger benefit from smaller diameter exhaust pipes or primaries, say 1.5" down and 2.5" back? That's what I had originally planned before I thought of the supercharger, or should I go with 1 5/8" - 3" back? Or even hedman tork-steps 1.5-1 5/8 to 3"?

Aside from the engine, I'm going to be picking up a locking differential... with the SC, should I keep the 2.73's? Or change to 3.08, 3.23, 3.73? I imagine going with 3.73's with a bit taller and wider tires will help with traction, plus I need to take change the two fronts anyway. Something along the lines of 275/50R15 or 255/65R15s (for the rears). Keeping the 215/65R15 stocks up front... that'd keep the RPMs down a bit along with OD..

Anyway, any help, thoughts, or suggestions would be great.

 

First, let's scrap the idea of the blower, that's just adding front end weight you don't need, and for the same money you could get better results from a 350. Which would be the wisest approach. Build the 350 while driving the 305. But figuring a 305, keep the compression up to help compensate for the lack of displacement, The smaller bores are helpful for avoiding detonation. Besides, high DCR is good for mileage. If you can get it to crank at 200 psi, you'll be sitting pretty, but this is near impossible to predict unless you're copying a known build. For a N/A 305, 1.5" headers would be best. Another reason for forgetting the blower is that with tall gearing, a 9.5:1 355 will get just as good mileage as an 8:1 305, blown or un-blown. A single 2.5" exhaust is a bit small for what you seem to want.

 

I wasn't talking about stall, I was talking about MPG.

I suppose we can agree to disagree. You need enough stall on the track to get the engine into the powerband. Up to peak torque is the typical approach for strip-only.

And, I maintain that even though my current converter stalls at 2500 RPMs, it feels very natural on the street. Lets the engine do its thing without that "spun up but going nowhere" feeling.

 

A dragstrip-only car can have the stall as high as 500 rpm below the torque peak. And up at 2400 rpm, the engine is spinning fast enough that SEFI is no mileage advantage over a well-dialed-in Q-Jet. Down at 600 rpm, the SEFI is a huge advantage.

 

Thanks for the "input"... Can we take the arguing elsewhere?

 

What arguing?

 

"My stall converter is bigger than yours"

 

If you thought that was arguing, you completely missed the point of the discussion.

Bottom line: You're on the wrong path toward accomplishing your objective. "More power" does not mean "more economy". "More power" means you're pumping more air and fuel through the engine, which isn't what you want for better fuel economy.

"Efficiency" is a different matter. You can get better fuel economy out of an engine by making it more efficient, which may also make it capable of more power. Case in point - LS1's - capable of better fuel economy than any 3rd gen V8, but a lot more power on tap.

 

I agree with five7kid, and FYI, he and I have been friends for some time. You can learn more from people's disagreements. He and I are both getting at the same point, (as we just discovered by PMs) from opposite directions.

 

If you thought I was being serious, you completely missed the point of the . Seriously though, more input on topic would be great. You asked for 1,2,3, and I gave 1,2,3 and more.. a bit more insight would be great. Stall converters aren't really relevant to the topic..

 

FWIW (not much, no doubt)

 

Then 2, because 1 and 3 will both cause you more misery than 2. The goal is to end up with a car that's fun to drive, cheaper than just buying a fun car.