Re: V-8 Milage

[farna@xxxxxxx]

This is why IHC used a 2V carb on the 401 - better low speed torque than a 4V carb, and it also served to limit rpms. The small valves increase velocity and turbulence in the combustion chambers. You need both at lower rpms to help combustion. Bigger is not always better! With the big valves the engine would have had more power, but the torque rpm range would have moved up higher and low rpm economy suffered. A 360 with 304 heads should react in a similar fashion. Throttle response was so good because of the charge velocity, but it runs out of breath quick too. I doubt you could have got that engien to turn much over 4500 rpm, 5000 at the most! 


On May 9, 2005 Bruce Hevner wrote:
> I did a little experiment with kinda the same type thing. I had an 86
> Caprice Estate Wagon. I jerked out the 305 and tricked up a 350. Here's what
> I did. Most of this would apply to an AMC too although you might have
> trouble coming up with the same parts.
>  I decked the block so the "Squish" was .035. I used TRW flat pistons &
> dished them in a "D" shape to match the combustion chamber and to achieve a
> true 8.5 ratio.
>   I used 305 2-bbl heads that used 1.720 intake and 1.5 exhaust valves. I
> used an Isky Mile-A-More cam (VERY short timing). The whole engine was built
> with 4000 max RPM in mind. I had the trans rebuilt and shortened up the
> shift points to 4200 max.
>  I installed a crank scraper to keep the oil off the rotating assembly.
>  I hit it pretty close, you could feel the power start falling off about
> 3800. The thing had FANTASTIC throttle response and would actually turn the
> tires a few times from a dead stop.
> I used Michelin "energy" 225x15 tires (supposed to give better mileage).
>  On the hwy (loaded 4 adults) it would get 19-21 MPG,,, at 85 MPH!!! If I
> slowed to 65 it jumped on up to 23-24. Around town 18-19 was about it. But
> as above,, this thing was a BEAST weighing 4400 lbs! So essentially I had
> the power of a 350 with the mileage of a 305. It had 235k on the clock (110
> on my motor) when the rear gear went south and I sold it.
> Bruce Hevner
> 
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