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Topic: Horespower and torgue improvements to the small block Chevy 350 (Read 1187 times) previous topic - next topic
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Horespower and torgue improvements to the small block Chevy 350
I have just recently purchased a very nice 1989 LD 22/MMH with 75K original miles. The 2nd owner had the LD for 25 years. He had it service regularly for the general items, He did not do shocks and other mechanical maintenance (PM) very well. I am a 30 year Navy Veteran so Preventative Maintenance (PM) is in my blood. I am beginning this at this time.

After driving this for a little while I have decided that there needs to be some improvements in the 350 SBC power plant. As it has been pointed out to me there is only one (1) Horsepower for every 44 LBS.  Dry weight of the LD. If and when my wife and I hit the road there are some pretty long and steep mountain passes in the areas that we plan to go to. We live in the Great Pacific North West, up on the Kitsap Peninsula, where there are a lot of little hills and some short mountain ranges  In short What have some of the other owners of these neat little coaches done to improve their horsepower to weight ratio.

Tom Dangelo
Poulsbo Washington
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #1 –
Tom,

Welcome to the LDO forum, and thank you for 30 years of service!  I'm sure some of our resident experts will be chiming in soon.  Congrats on your new LD!

Greg & Victoria
2017 Mid-Bath  “Nocona” towing a manual 2015 Forester
Previously a 1985 TK
SKP #61264
Re: Horespower and torgue improvements to th small block chevy 350
Reply #2 –
Thank you for the warm welcome. I have had 2 Cortez motorhomes hence the name cortezit, I look forward to many adventures and trips to see the country that we, who have served, stood ready to die for. From all that I have seen of the LD community and the  fine coaches of its members I am certain that I have found a very nice group to be a part of.

Tom aka "hey you"
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #3 –
Hi Tom. Welcome.   You might want to mention if your LD has the throttle body injection or a carburetor.  I believe your model year is right at the switch over point.  I’m not enough of a Chevy Truck gearhead to mention useful upgrades. 
Currently: 2008 36' Tiffin Open Road
Previously: 2007 Mid Bath
Re: Horespower and torgue improvements to th small block chevy 350
Reply #4 –
Thank you for the observation. It is indeed a TBI motor


.
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #5 –
In the old days when doing SBC engines, we wanted more torque, a camshaft change would get you started towards the right direction.
Jota
96 23.5 FL
 
Re: Horespower and torgue improvements to th small block chevy 350
Reply #6 –
Thank you for the response. I have decided to change the heads to a 64cc chamber head a performance, TBI intake manifold,
Roller Camshaft, Roller Lifters,  and Roller tip Rockers plus a couple of other items that I am exploring, basically converting the earlier era SBC to a platform more similar to that of the 350 Vortex engine. About $2200 and change for parts plus some sweat equity in labor. Increase the fuel pressure to 18PSI and add a heated O2 sensor. I have built numerous engines over the years so this will give me a chance to get grease under my fingernails. I will let you all know the results when it is completed.

Tom
A diamond cannot be polished without friction
Nor a man perfected without trial.
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #7 –
Just a couple years after yours Chevy offered a four speed automatic.  I am not sure if there is a change in the lower gears, I believe the extra gear is a overdrive.  It also might be worth while seeing what cooling upgrades can be done.
Currently: 2008 36' Tiffin Open Road
Previously: 2007 Mid Bath
Re: Horespower and torgue improvements to th small block chevy 350
Reply #8 –
Quote from: cortezit  - 
Thank you for the response. I have decided to change the heads to a 64cc chamber head a performance, TBI intake manifold,
Roller Camshaft, Roller Lifters,  and Roller tip Rockers plus a couple of other items that I am exploring, basically converting the earlier era SBC to a platform more similar to that of the 350 Vortex engine. About $2200 and change for parts plus some sweat equity in labor. Increase the fuel pressure to 18PSI and add a heated O2 sensor. I have built numerous engines over the years so this will give me a chance to get grease under my fingernails. I will let you all know the results when it is completed.

Tom
A diamond cannot be polished without friction
Nor a man perfected without trial.
Tom, both Larry and Steve have had older TBI LDs and can probably give you some practical advice if you can wait for them to chime in.
Chris
Formerly: 2002 30' IB
Re: Horespower and torgue improvements to th small block chevy 350
Reply #10 –
Thanks Chris, Life is a journey and not a race. I can wait a while.

Tom
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #11 –
You may want to take a look at this book.  David Vizard's How to Build Max Performance Chevy Small Blocks on a Budget.
There are a couple of suggested rebuilds for a a LOT more torque at lower RPM. Probably the best thing is a good set of heads that flow well in the lower to mid RPM ranges, tied to your cam. Edelbrock and AFR come to mind. You may want to upgrade your TBI system to a Holley Injection setup through the manifold vs the throttle body. Make sure your trans is able to take the extra torque. Keep the motor and trans cool. Since your going this far into the motor, you may want to look at a fresh high performance block or complete engine from Chev or other vendors. Might save you quite a bit of time, plus a warranty too.

If you really want to go deep, look into using an LS engine. They respond well to minor upgrades with gobs of horsepower and torque. Again, your trans maybe the limiting factor at this juncture. It all boils down to how much money you want to spend :)

 
1997 RB
Re: Horespower and torgue improvements to th small block chevy 350
Reply #12 –
Horsepower is only s matter of $😋
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #13 –
I will probably complete the suspension upgrades to gas schocks and Hellwig Sway bars before doing any thing to the power plant. I have a complete Holley 4 barrel fuel injection system that I have never used. It is tuneable with a laptop. That and an Edelbrock intake. Headers , depending on how much I can get under there. Will look around for some adaptable vortex heads
. I have built a couple SBC in the past. Will do some computer forecasts with different parts to see what I can come up with. I have a 1987 Grumman on a P30 platform that managed to squeeze another 100horses out of.
Tom
The Brown Banded Turtle (TBBT)





1989 22' G30
Re: Horespower and torgue improvements to the small block chevy 350
Reply #14 –
We suffered with our 1983 LD's anemic 165-HP engine and the overloaded suspension. And was it equipped with the optional dual exhaust, with a cross pipe, and the "Dyno" kit (different main jets and distributor centrifugal advance springs).
The suspension had been extensively rebuilt and upgraded.

I considered several options to improve the mileage and power.
Two issues stopped me from dumping any more money into it.
First was the lack of overdrive. The three-speed Turbo 400 is a fine transmission but without overdrive, and 4.11 rear axle ratio, the engine is spinning at high RPMs, at cruising speeds, one of the reasons why so many Chevy 350 V8s wore out early.
At 85,000 miles, our 350 needed rod bearings and a timing set.
The other reason why the 350s had short lives was the relatively small radiator, many of them burned up before the wore out.
If upgrading the engine, make sure to get the best radiator available. Our  '83 had a thick, dual-core radiator and it still ran warm on long, hot uphill grades. A radiator sprayer was eventually installed to keep the temps in a more tolerable range.

Consider why the stock engine seems underpowered. It is a truck engine, designed to run at high RPMs, for extended periods,  without burning the valves. The small valves limit the amount of air and fuel flowing through the engine, reducing the heat build up in the cylinder heads. Regular car engines are not designed to run at full throttle for extended periods.

I searched for an early to mid 90's Chevy 350 V8, mated to a 4L80E 4-speed overdrive transmission, to use for a transplant but never found an affordable one. Also considered building a 383 V8, along with a 4L80E., but once again it was too much money, IMO, to put into the lightweight chassis
Ford and LD finally came to our rescue in 2003 by producing the 23.5' models with the E450 chassis.
The V10, and E450 chassis, is superior to the Chevy G30 in almost every way.
in 16 years on the forum, I can't remember anyone overheating and destroying a V10.

Keep us posted on how your project turns out.
Larry



Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Horespower and torgue improvements to th small block chevy 350
Reply #15 –
Larry, et al; I have now amassed all of the components to go forward with the  upgrade. We do not have a chassis dyno to deliver definitive results but the program that we do use, "desk top dyno"  indicated about 315 HP and 375 FT LBS
 of torque at 4200 rpm.

This in theory brings the HP/WT ration from 1HP for 44 LBS of empty vehicle wt. down to 1hp to 25 LBS of empty vehicle WT.  I have built and raced rice rockets along with other engines. My moto has always been "If it sounds good in my ear and feels good on my rear then I am happy. We will see how big a smile I can generate. I can carry spare TBI components in case I need them, along with spare belts and hoses I will be prepared to go anywhere., with reason of course:):)

PS My Helwig sway bars are on the way as well. I have already replaced all four shocks with Monroe GAS- Matic's. Not top shelf but then I am not road racing.

Tom and the Brown Banded Turtle
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #16 –
Note that in CA, none of the mods to the engine would likely be CARB approved, and thus would prevent a pass on emission testing. I guess you have determined this does not apply to WA emissions?

Steve
2004 FL
2013 Honda Fit
Re: Horespower and torgue improvements to th small block chevy 350
Reply #17 –
“Note that in CA, none of the mods to the engine would likely be CARB approved, and thus would prevent a pass on emission testing. I guess you have determined this does not apply to WA emissions?

Steve”

Steve in Wa. Vehicles over 25 years don’t require testing.
Lynn and Lori
Re: Horespower and torgue improvements to th small block chevy 350
Reply #18 –
Not having lived in California since I retired from the Navy, almost 28 years ago I am not up on the current emission standards imposed on those who still live there. I have researched each of the components that I am using. Summit racing has a CARB compliant notice stating that each component is CARB Compliant.  

A diamond cannot be polished
nor a man perfected without trial.

Tom and the Brown Banded Turtle
1989 22' G30
Re: Horespower and torgue improvements to th small block chevy 350
Reply #19 –
Although this does not apply to your WA registered vehicle, you could check this page to verify whether your parts are CARB certified for your specific engine:

Database: Aftermarket Parts Database of Executive Orders

Steve
2004 FL
2013 Honda Fit
Re: Horespower and torgue improvements to the small block Chevy 350
Reply #20 –
Thank you Steve for the link to this data base. It is interesting that this website database is germaine to vehicle registered in the State of California. It does not seem to be applicable to the other 49 states. Perhaps I am wrong?? Maybe you meant for me to look at it because I said that the components that I am using were CARB compliant??

I was born in San Diego in 1942. I am currently living in the Great Northwest where these laws do no apply to my vehicle, in this case.

Tom Dangelo.
1989 22' G30
Re: Horespower and torgue improvements to the small block Chevy 350
Reply #21 –
Correct. Were you or a subsequent owner to attempt to register this vehicle in CA in the future, this would be an issue. CARB certification is the most stringent of any state, so obtaining that allows a supplier to sell the part countrywide. Of course, installing all CARB-certified parts does not guarantee a clean engine will pass emissions testing - just that in CA, you won't be required to dismantle your engine even if it DOES pass...

I mention all this because our '83 4bbl G-30 LD had no CARB-certified components available to allow conversion to TBI or port injection. Our only options would have been to install a complete oem package from a subsequent year, down to the heads, tranny, computers, and all bolt-on hardware, OR cram in a 454 and put CARB-compliant mods on that. So, we lived with keeping our travels below 10k' for 19 yrs...

Steve
2004 FL
2013 Honda Fit
Re: Horespower and torgue improvements to the small block Chevy 350
Reply #22 –
Steve how well I remember having to go the referee station when I was living in California. It was always a pain in the hindquarters. I am saving all of the OEM stuff that I have removed from it. If and when I sell it I will transfer all of it along with the title to the subsequent owner.

Tom
1989 22' G30
Re: Horespower and torgue improvements to the small block Chevy 350
Reply #23 –
Washington State has less restrictive emission rules than California, many vehicles not needing any inspection if garaged in the right county.
Even in California, a modified engine can pass if the visual inspection finds nothing unusual and the engine runs clean, without any OBDII codes showing (Check Engine light).
Sometimes the biggest problem is passing the visual inspection. Painting the engine the Factory color and making sure everything looks stock helps, adding a layer of dirt and grime is even better.
Resist the urge to add chrome and/or shiny, colorful parts.
Both of my Jeeps have modified engines and pass the emissions test easily. While I have the CARB certificates for the parts installed, I have never been asked to show them .

With the built Chevy 350, I would want the biggest cooling system possible, it will be the RV's weak point.
If equipped with catalytic converter, it will probably need a higher flow model, to cope with vastly increased exhaust flow.
Hopefully, your LD came with the optional dual exhaust system.

It should be an interesting project.
I'm glad it's not me who has to remove and replace the engine. I replaced the 350 V8 in a Chevy van I once owned.
Once was more than enough.
Get a big shoehorn. I have no idea how GM squeezed a big 454 block engine into the narrow engine bay, the 350 is a tight fit.

Let us know how this works.
Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Horespower and torgue improvements to the small block Chevy 350
Reply #24 –
Well Larry the weather up here in the Great Northwest is finally getting to a point where we can tackle the project. So this is the month that we will do the deed. I will keep you posted as to the outcome.

Tom and the
 Brown Banded Turtle.
1989 22' G30