Big_John wrote:
In the industrial engine, yes, Chrysler did their homework and I'm sure the valve size is great for that application. A motorhome? I don't know. First you've got more cubic inches to feed. There's no getting around that. Then you're not running at a constant speed like you are with a stationary industrial engine. I think the small valve may narrow the power band. Under 3000 RPM may be fine for you, but for me, climbing steep hills and sometimes towing a car trailer, there are times were the RPM in my motorhome goes over 3000 RPM.
Honestly? It may work fine. Chrysler used the bigger valves in all the 440's they built though. They never saw the need to use a smaller valve.
Try it and report back. Its got me curious.
In the industrial engine, yes, Chrysler did their homework and I'm sure the valve size is great for that application. A motorhome? I don't know. First you've got more cubic inches to feed. There's no getting around that. Then you're not running at a constant speed like you are with a stationary industrial engine. I think the small valve may narrow the power band. Under 3000 RPM may be fine for you, but for me, climbing steep hills and sometimes towing a car trailer, there are times were the RPM in my motorhome goes over 3000 RPM.
Honestly? It may work fine. Chrysler used the bigger valves in all the 440's they built though. They never saw the need to use a smaller valve.
Try it and report back. Its got me curious.
First ... this motor was designed and put in way more MHs(and trucks) ....than "industrial" by far. Are you aware that there were TWO "industrial" motors ? ... the 413 and the 361.
In a MH application you ARE running a basic "one rpm" for most of the running time. For SURE it narrows the power band AND the max output ... but I would rather have a motor that will run it's best in the range of 800-4500 than one that will run up to 6k. But is this just me?
Those HEADS are the reason why Chrysler dropped the 413 combo. That total motor cost Chrysler 250$ more PER UNIT ...than the 440 that it replaced. The exh valves? ... were sodium filled. They cost almost 50$ each(at the dealer) ! .... the rotators cost a TON too. ALL those items add-up ...big-time.
Try what ? ..... the flow work ? .... my intent is to get the fuel/air mixture automized the BEST .... at and around 3k. If this means epoxing up the intake ports ...so be it.
The best Mopar big-block heads are the later open-chamber ones, from the 1968-ish 906 to the last of the 400 & 440's in 1978. In fact, the later ones are BETTER, since they all have hardened exhaust seats for unleaded gas.
John and Elizabeth (Liz), with Briza the size XL tabby
St. Bernard Marm, cats Vierna and Maya...RIP. ">
Current rig:
1992 International Genesis school bus conversion
Jarlaxle wrote:
One major reason the 413 uses smaller valves is very basic: it has a smaller bore than the 440 (all RB's have the same stroke), and the larger ones simply do not fit easily. IIRC, most of the HD 413's & 440's (and most "dash-3" engines in general) are governed to under 4000RPM. There's no tach in my friend's class C (1974 B-300, 440-3), but the engine is certainly not a revver.
The best Mopar big-block heads are the later open-chamber ones, from the 1968-ish 906 to the last of the 400 & 440's in 1978. In fact, the later ones are BETTER, since they all have hardened exhaust seats for unleaded gas.
One major reason the 413 uses smaller valves is very basic: it has a smaller bore than the 440 (all RB's have the same stroke), and the larger ones simply do not fit easily. IIRC, most of the HD 413's & 440's (and most "dash-3" engines in general) are governed to under 4000RPM. There's no tach in my friend's class C (1974 B-300, 440-3), but the engine is certainly not a revver.
The best Mopar big-block heads are the later open-chamber ones, from the 1968-ish 906 to the last of the 400 & 440's in 1978. In fact, the later ones are BETTER, since they all have hardened exhaust seats for unleaded gas.
Huh ??... !!
One style of the 413 had the LARGEST exhaust valves that were ever put in any B/RB-engine !!
Jayne and Ringo
And a 440 is a better choice ...... the whole motor, heads -- what ?
Jarlaxle wrote:
The 440 is a better choice, carb to oil pan. There is no case where I would prefer a 413.
The 440 is a better choice, carb to oil pan. There is no case where I would prefer a 413.
And what about the 440 is better ? ..... for an RV application. I can only think of two things that some might think as "better".
EVERYTHING else ...... the block, heads, intake-heating, crank, rods, cooling-system, pistons - etc ..... is far FAR better.
And I see you did not comment on the additional shrouding "issues". GOOD move.