Looking at picking up a 81 c30 crew cab with a 350 and sm465 ,not sure of the rear gears yet, its 2 hours away , but its a small block 350 truck and I have a LO5 short block , zz4 cam and some 193 heads laying around, Think this would be a decent tow engine vs the 180hp smogger in it now?
It would honestly probably be worse with the 193 heads as they don't flow very much. The L05 is a good block for building on. If I were you I'd use the heads off of the old 350 on the new L05 block, and get pistons with smaller chambers to up the compression.
The operative word is TOWING. Swirl Port heads will run off the table around 4500rpm. If you think you will be in that idle-4500 RPM range; they'll be useable. Thats what they were designed for (assuming the valves, guides, springs and the castings themselves are all in good shape). IS it roller-cam ready? Im not sure if the ZZ4 cam is a good one for towing or not; I'd defer to Eric, Bogie, Joker, Vinnie; et al. If not that cam then probably something like the stock GM 305 cam, along with a basic dual plane manifold and a small carb with HEI will round it out nicely
I'd go high rise dual plane intake (with exhaust crossover heat if running in freezing weather) and a 650 - 750 vacuum secondaries carb... and the '81 heads like Eragon suggests... swirl port heads can't flow enough for a ZZ4 cam...
well the 193s are really close to the 882 flow number but I'm sure they are way more efficient and have a better compression ratio, also I am sure they will work better with the roller cam setup, BTW how do you think the ZZ4 cam would be for towing?
That cam peaks out on HP at 5500 and torque at 3500 in the ZZ4 motor. So my guess is too much cam. Figure what heads you're going to use and what the static compression ratio will be and pick a cam that'll run below 3500-4000. I think you'd be miles ahead finding a set of used Vortecs that pass the magnaflux test.
Did anybody ever flow the 193 heads? Didn't think anyone ever bothered... the 882 heads max flow at 204 CFM/141 CFM... better than the -113 ZZ4 heads... The 882 heads max out about 375 HP at 5750 RPMs with a ZZ4 cam and good compression ratio pistons... the Swirl Port heads die about 4500 RPMs and 250 HP, but are torquey and efficient below that...
These are some Flow numbers from someones test on Thirdgen.org.
INTAKE
Stock SP #193 . Modded SP modded Vortec
.100 70.7 68.1 55.8
.150 101.7 100 89.2
.200 124 125 123.5
.250 140 144 160
.300 146.5 154.7 186
.350 150.1 164.8 203.8
.400 154.7 171.3 228
.450 158.2 175.4 235
.500 160.4 177.4 228
EXHAUST
.100 47.8 51.7 42.9
.150 70.4 73.1 66.6
.200 85.1 93.7 90.1
.250 97.6 112.3 112.2
.300 112.3 129.7 129
.350 120.5 145 142.6
.400 125 156.3 152.6
.450 129.2 164.6 160.9
.500 129.2 162.5 166.5
The following parameters apply:
1. None of the heads had a three angle seat cut.
2. The L31 and stock 193 head used a single angle cut on the valve.
3. The modded 193 head used a 30 degree back cut on both the intake and exhaust valve.
This truck could have anything from 3.73 ,4.10 or 4.56s , so around here the Speed limit being 70 mph on a skinny *** 2 lane backroad I'd be running 2,786 to 3406 RPMs with a stock 31.75 tire so Roller cam recommendations? Prefer a gm takeout VS buying a Brand new aftermarket roller for price .
Yeah, the stock 193 head max flow was weak... 150's/120's CFM max by .400" lift (what we look at for street engines)... and the swirl ramps block off about 1/3 of the intake ports... and they cause excess turbulence at high flows/high RPMs...
ZZ4 cam torque peaks around 3,000 to 4,000 RPMs, so strong in the RPM range you cited...
I'd use a ZZ4 cam for light to medium towing, up to about 5,000 pounds... above that prolly want a bit milder cam... maybe an '87 TPI 350 202/206 roller cam... which I may be taking out of my '87 GTA in the Spring... if you find a similar truck...
New Plan.... guy has a 87 choo choo dually with no engine or trans that was a 454 /sm465 truck, and another guy has a 96 454 /nv4500 cab and chassis, so im thinking get both and merge em togeather....the 96 has good wheels and tires and a 454 with a 5 speed and every wire needed for the swap , so I can get my moneys worth out of it and sell the cab and frame for scrap.
I remember when we first started using dually crew cabs and goose neck trailers. Gas was about .35-45 cents per gallon. Almost overnight it went to $2.00 a gallon. I recall putting Almost a full pay check in to fill the 125 gallon bed tank and the two saddle tanks to go racing. We never got better than 5 mpg towing and about 8-9 around town on a good day. The first round of match racing had to pay for gas.
I guess even with the updated motor and manual trans you will be hard pressed to break 10 mpg. Nice truck though.
That 7.4 liter/454 rpo L29 is rated at 290hp@4000rpm/410lb/ft torque@3200rpm.
The 1990 454SS weighing 4400lbs with the L19 TBI 454 was rated at 230hp@3600rpmrpm/385lb/ft torque@1600rpm and had an EPA rating of 9mpg city/10 mpg highway
The 91-93's got the 4 speed with overdrive trans (4l80e) and the 4.10 rear gears. The L19 engine was uprated to 255hp@4000rpm/405lb/ft torque@2400rpm. It had an EPA rating of 9mpg city/12 mpg highway.
A couple guys I know have the L29 454, one in a Suburban, the other in a 3/4 ton ecab 4wd, they both get around 10mpg in normal driving, with the Burb getting 12.5mpg during highway trips.
Yeah, Hogg, that was my first thought as well... some of those 1970's - 1990's 454's would need a "MPG REBUILD" before I would ever consider using them...
Even the 1990's Jeep Grand Cherokees with small block Chrysler 360" V8 were rated a mere 9 MPG city / 11 MPG hiway...
Gas is relatively inexpensive now, but the oil companies will be throwing big money into changing that as fast as they can...
OK well the tax refund hasn't gotten here in time and to make things worse I got a letter from the IRS saying they need more info for something, So the 454 5 speed donor got sold , and I sold my van and Picked this up yesterday for a steal, It was so clean I couldn't pass it up, its a C20 with the C6P Heavy duty Chassis package and is a Silverado Package. 350 th400 interestingly enough this can hold a bigger camper than the dually but just 100 lbs less weight . I went and looked at it and it wouldn't hardly run, y pipe is broken and held together with a tin can and a worm clamp , I managed to drive it home 25 miles at 65-70 mph got it home and tinkered with it to find out its got a big vac leak under the carb adapter , the dist was super loose, it is in sad shape. The ad said it had a rebuilt engine with 1000 miles ,, needless to say when i asked the guy about it he couldn't seem to locate the paperwork ..lol I could see by the 2 inches thick of grease on the block it wasn't rebuilt but did seem to run OK on the highway.
after tinkering with it, figured out the Knucklehead that put the carb and carb adapter one, used the thin gasket between the adapter and qjet and the rear bolts where too long and caused te spacer to raise up off the intake and caused a huge vacuum leak..lol I bet they where pulling their heads out trying to figure out why it wouldn't run right.
Looks like it's in decent shape... keeping an eye on oil consumption will give some kind of indication of engine condition... it has dual fuel tanks, but hope it doesn't need them too much... it was -0- F. here Saturday night, so we would need that aircleaner heat setup working to keep the carb. internal condensation from freezing up...
Good thing I'm in Tx. It was in the 70s yesterday..lol Got an exhaust installed but it still leaks around the manifolds due to they are not the correct manifolds for this truck, so the y pipe isnt sealing correctly, I did run the numbers on the engine though, 300hp 350 from a 70 impala, and a set of 73 993 yeads, so its a hell of a mess I'm looking for a vortec 350/4l80E swap now.
I'm jealous of the the weather and the truck - lol. When Buzz was at -0-, that same weekend we got to -19. Finding that truck in the condition it is in is impossible here in the rustbelt. Looks pretty nice - congrats.
Good thing I'm in Tx. It was in the 70s yesterday..lol Got an exhaust installed but it still leaks around the manifolds due to they are not the correct manifolds for this truck, so the y pipe isnt sealing correctly, I did run the numbers on the engine though, 300hp 350 from a 70 impala, and a set of 73 993 yeads, so its a hell of a mess I'm looking for a vortec 350/4l80E swap now.
Well took the valve covers off to replace the gaskets and its got one 993 and 1 882..lol I might just slap this set of LO5 heads I got on it..lol just ordered a new summit street strip carb to replace this worn out qjet.
Looks like a pretty solid truck Jim. If the engine runs pretty well you might have a good candidate for a build, but the upgrade to a vortec has many advantages, the vortec heads, roller cam setup, and the 1 piece rear main seal. According to the '85 C/K truck information kit available from the GM Heritage Center The GQ1 rear axle with a 350 and automatic transmission is a 4.10 ratio, so you got something there that can really pull, an OD transmission would be a big improvement, bringing the rpm down for hiway cruising. The oem LT9 350 is setup for heavy duty, the heads were equipped with the 1.72" intake valves.
sorry I didnt update this , I got a nice exhaust installed and got the truck running pretty good with a new summit cab, but the engine had a burt valve on No. 8 , school wasnt for me I traded the truck for a 86 halfton , and then traded that for a 92 dodge van that had a bad ecm and hadnt ran in like 4 years, but a good JY ecm and it fired right up I got restless and packed all my stuff in it and drove back to N.C. and that turned out to be a nightmare so I made my way back to TX and started with new junk.. my new 97 ext cab v6 5 speed doing alot more work than it should I just picked this 2000 tahoe limited up for a steal.
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