engine quieter with new e7 heads?

[oldiron]

We got the engine re-installed last weekend and finally got to drive it a few days ago. The old combination was 68 block with flat top pistons, D9 rail rocker type 70cc heads, and a stock style cam. New combination is...same block, with E7TE-PA heads, Melling MTF-1 cam. Same factory intake and 2bbl carb. This combination is dramatically quieter at every rpm level. Before, on the old combination, at 2500-2800 on the highway, the engine was loud and holding a conversation was mostly yelling. Even my 17 year old daughter commented on how much quieter it is. Anyone ever experience this? I realize that cylinder heads make a huge difference, but this is night and day. So far I'm MUCH happier with it this way.
Greg

 

[nvrstuk]

-so the exhaust is hooked up properly this time?

-lifters/rockers are set at proper torque/lash?

-less air going thru the engine would allow your mufflers to effectively muffle that reduced amount of air more effectively (think of how quiet an engine is at 2K rpm compared to 4K rpm)

- an engine that makes significantly more power with "better cam & heads" will be louder with the same exhaust, same proper exhaust connections, mufflers and piping. It always will because more air is flowing thru the same exhaust system.

 

[jckkys]

I'm going to assume the engine is a '77 with the 69cc heads. These had a 4 degree retard of cam timing and 8.8 to 1 compression ratio. Now your CR is about 9.5 to 1. The cylinder pressure at the point of the exhaust valve opening was likely higher than the new combination. The Melling cam may have more influence on this than the heads. Call Melling and ask them. In designing the cam they take all these factors in consideration.

 

[oldiron]

Same everything except the heads and cam. To be clear "or clearer" I was referring to the mechanical sound of the engine itself, not just the exhaust note alone, although that is different too (hard to describe...less rumbly more tinny).
As stated before, the engine is a '68 302 from a fairlane. Rebuilt years ago with the 79 heads.
Couldn't be happier with it so far, just curious what others thought.
Greg

 

[jckkys]

You had only described the engine as a '68. No mention of the donor. I knew '68 Broncos with V8s got 289s. So that was my first guess. Regardless, mechanical noise from an engine is usually not good and the heads are the last place to look unless it's valve clatter.

 

[nvrstuk]

Good to have the rest of the information needed so we could tell you it is/was rocker/lifter noise...

 

[blubuckaroo]

At this point, who knows about your old heads?
But, E7 heads are better than your old ones with less monkey motion and way better flow.
I just don't like pedestal rockers. It may be just a personal opinion, but roller rockers have more adjustment and can handle more cam pressure.

 

[jckkys]

I guess we couldn't be very helpful. As nvrstuk said, the new combination should be louder not quieter as it turned out to be. Still Melling would have to consider all these factors when engineering the cam. So they would be the most likely to know why the engine is quieter.

 

[suckerpunched]

how is the power compared to the old setup? any noticeable difference?

 

[56f100bbw]

This might not compare but my 77 is the original engine rebuilt and my 76 is a 1990 Ford engine 302 Way quieter than the 77 almost too quiet runs great on a carb

 

[oldiron]

how is the power compared to the old setup? any noticeable difference?

Mid range(2000-3000) is noticably better, upper rpm(3000-4000) are smoother/quieter, but can't really tell if its an improvement. The only part that suffered is the extreme low rpm grunt. Old cam/heads could be lugged down to 800 and still pull effectively, new setup doesn't like to start pulling till around 1000-1100. ( But that was expected).
Greg

 

[jckkys]

Larger ports, valves, carburetors, headers, and longer duration cams are all designed for high RPM HP. Low RPM torque is reduced. The power band is narrowed too. Lower gearing and more gears are needed to take advantage. The only way around this is increased displacement. There is realy no replacement for displacement. Forced induction helps too.

 

[WheelHorse]

At this point, who knows about your old heads?
But, E7 heads are better than your old ones with less monkey motion and way better flow.
I just don't like pedestal rockers. It may be just a personal opinion, but roller rockers have more adjustment and can handle more cam pressure.

I used my stock rockers with the crane conversion kit.