I’m starting with a 1986 Winnebago Chieftain 33, with 24,570 miles (happen to know because it just got inspected), for which I paid $3600 (I think – somewhere around there.)
Haven’t had time to do much with it since buying it last October, but enough to convince myself that it’s a keeper.
We’re about to put our house up for sale, and I have a commitment from my wife of $10k of the proceeds for “my stuff” on the motorhome – suspension upgrades all around, headers (
1973-91 GM / Chevrolet 396-454 BBC Pickup / Suburban / Blazer (2wd) Tri-Y Headers (7/8) and exhaust for sure, dual-plane manifold as well … beyond that … still plotting … Oh yes, I scored a low-mileage Jacobs ignition module on Ebay, so that’s in the cards as well.
My wife and I lived aboard a 1916 sailboat for many years, so while we’ve never lived in a motorhome, we are pretty confident we can make it work, at least in limited doses.
Or goal is to be able to get away from the harsh winters, and freeload off old friends across the land 8^)
I am cognizant of the fact that I will never put enough miles on it to pay back any potentially mileage-enhancing modifications, at least not in terms of dollars. What I want is reasonable performance, acceptable economy, and above all, efficiency; and what I mean by that is I just want this engine to be operating optimally for this application, reasonable?
Also, I am capable of doing most, or all of the intended upgrades myself, if need be, however, I also have two friends who are professional mechanics, both of whom I trust, willing to assist, or be assisted by, me – only problem neither of them has a bay that will accommodate the coach, but neither has balked at the prospect of doing the work in their lots.
So again, headers/exhaust and intake are a given, as is the ignition module, and probably an upgrade distributor.
Next in order of likelihood is a strong RV cam; probably hydraulic roller. At the moment I’m leaning toward this one:
COMP Cams: Xtreme Energy™, XR252HR: Cam & Kit
but subject to revision.
I’ve done this job before, with the engine in the vehicle, and that’s one reason it’s on the second tier of ‘to-dos’, however, I really know that as part of the entire upgrade package, the right cam will result in a synergistic improvement.
{Parenthetically, a B&M 4L80E 4-speed OD transmission, lock-up torque converter, aftermarket controller, shortened driveshaft, etc. are also in the cards.}
Arriving at last to the topic at hand, heads:
I have no issue with the ability of the peanut-port heads to flow just as much as I am ever likely to demand, and with the availability of a well-matched manifold (
https://www.summitracing.com/parts/w...2wnd/overview/) specifically for the peanut heads, I would probably be very happy with the results.
On the other hand, unless I am mistaken, a set of closed-chamber (100cc) oval-port heads (iron or aluminum) will combine with my flat-top pistons to yield a 9.0:1 – 9.2:1 compression ratio, which is much more in the range that I would target if building a performance street engine.
My question then becomes not: ‘is it economical?’ so much as: ‘is it advantageous?’
There are several aspects to this question.
My understanding is that the lowering of compression ratios, among other factors, reduced combustion efficiency, necessitating the addition of air injectors to promote post-exhaust combustion. If this is accurate, would this not be one factor that contributes to the premature exhaust manifold/gasket failure to which these engines are purportedly predisposed?
Now, I know that compression translates to horsepower, but the next part of my question regards how valuable this power is going to be in my application. I mean, these engines are going to make tons of torque regardless. Will I even notice the difference between a properly set up engine with the stock heads versus a similarly configured engine matched (as necessary) to the replacement heads?
Final data point has to be: what do I want?
Well, I want it to be as much fun to drive as anything that size is going to be. I’d like to be able to merge with traffic without coming to a full stop waiting for a space, and I’d like to be able to climb moderate grades without becoming a hazard to navigation.
And … when all that well-designed, well-tuned mechanical efficiency is not contributing to performance, I would like it to deliver some improved fuel economy.
I’m not so much concerned with the cost to fill the tank(s) as the ability to even reach that next gas station in a pinch. Call me paranoid, but I remember gas lines for miles, hot tempers, and even people shooting each other back in the late 1970s, and that is what’s really in the back of my mind when I consider fuel economy. [Or maybe getting beyond range of marauding zombies, or invading aliens …]
Anyhow, we originally planned on selling the house, getting another, and putting $15-$20k into a modest motorhome or trailer and tow vehicle, but then this came along, so we grabbed it. So now we’ve upped that a bit: I get $10k for ‘man stuff’ and my wife gets $10k for her stuff (nicer fridge, range, carpeting – yada yada yada …)
No, it’s never going to be a wiz bang diesel pusher, but from what I’ve seen these past few years, I’d be hard pressed to find such a vehicle for the $24k (including the new tires I’ve already installed) I have earmarked for this.
Thoughts?