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73-87 Chevy _ GMC Trucks => Performance => Topic started by: 77c10diesel on November 24, 2017, 12:18:11 PM
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I have an 85 K30 dually cab and chassis with a service box. It is a 4x4 with a 205 and a THM400.
I got this to tow a 34ft trailer. It has no smog stuff due to it being a K30 C&C. It has a Rochester 4 barrel on the stock 454. And, it has 17K original miles.
I need to get a little more power from this truck. I would rather not due any internal engine stuff due to the super low miles. It runs like a top, it just needs a little more gitty-up.
Oh, and it has 4.11 gears front and rear.
Would I benefit from a different carb, intake and cam swap? If so, what do you suggest?
There is no smog pump, so the stock manifolds are not restricted by the smog injectors. I would like to keep the stock iron manifolds if I can.
So, any suggestions that would boost the torque and HP a little?
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Try advancing the timing before you do anything else.
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I agree on the timing. A faster advance curve would help also I could give a suggestion for a performance curve but with you towing that trailer I am not sure you want it to come in that quick. With your reluctance to go inside the engine (not shaming I understand with those low miles ) most of the improvements will be hampered. A camshaft change would really wake it up like a Voodoo #10110702 if you ever change your mind. There might be an improvement with an intake change you have the pancake style right now. Try to find an old style q-jet intake if you want to go the factory route. The older style were more the high rise style. A high rise aluminum dual plane with the q-jet bolt pattern if you don't want to wrestle cast iron around ( I am 55 I like that choice lol). Keep the Q-jet it is the 800cfm version if it's original. Cliff Ruggles book on Quadrajets has some excellent tuning and rebuild instructions. A quality set of headers and a free flowing exhaust would help considerably. If you are dead set on the exhaust manifolds a set of better flowing mufflers at the very least. I have the same driveline in my K10 SWB and enjoy it daily. David
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The horrible compression ratio and crap heads are what’s hurting this set up. Putting a cam in it with heads that will only choke out any performance gain you would of gotten. Big block like to breathe and those heads are like you breathing threw a straw. A turbo would help. The low compression will work with a turbo and the air will be pushed threw. With a turbo you have good driving majors and power when you need it.
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The horrible compression ratio and crap heads are what’s hurting this set up. Putting a cam in it with heads that will only choke out any performance gain you would of gotten. Big block like to breathe and those heads are like you breathing threw a straw. A turbo would help. The low compression will work with a turbo and the air will be pushed threw. With a turbo you have good driving majors and power when you need it.
The sounds like a great idea. Have you done many BB turbo setups? I would just be worried with all that extra power a guy may have problems with the driveline. What's your experience with that? I am very interested.
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The horrible compression ratio and crap heads are what’s hurting this set up. Putting a cam in it with heads that will only choke out any performance gain you would of gotten. Big block like to breathe and those heads are like you breathing threw a straw. A turbo would help. The low compression will work with a turbo and the air will be pushed threw. With a turbo you have good driving majors and power when you need it.
The sounds like a great idea. Have you done many BB turbo setups? I would just be worried with all that extra power a guy may have problems with the driveline. What's your experience with that? I am very interested.
as long as you don’t put a sissy 700r4 behind it and keep boost down to like 6 psi. Anything higher then that you may run into converter issues. You’d need one with an anti ballon game plate. If your gonna do it with a 10 bolt id go with an 89-91 Burb or Blazer rear axle and if 4x same years 10 bolt front axle too. They make carb kits to convert a Holley to be used as a blow threw carb. I wouldn’t use a Slobberjet or Edelturd.
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The horrible compression ratio and crap heads are what’s hurting this set up. Putting a cam in it with heads that will only choke out any performance gain you would of gotten. Big block like to breathe and those heads are like you breathing threw a straw. A turbo would help. The low compression will work with a turbo and the air will be pushed threw. With a turbo you have good driving majors and power when you need it.
The sounds like a great idea. Have you done many BB turbo setups? I would just be worried with all that extra power a guy may have problems with the driveline. What's your experience with that? I am very interested.
as long as you don’t put a sissy 700r4 behind it and keep boost down to like 6 psi. Anything higher then that you may run into converter issues. You’d need one with an anti ballon game plate. If your gonna do it with a 10 bolt id go with an 89-91 Burb or Blazer rear axle and if 4x same years 10 bolt front axle too. They make carb kits to convert a Holley to be used as a blow threw carb. I wouldn’t use a Slobberjet or Edelturd.
I just bought a TH375 off a guy on Craigslist. Is that a good transmission? I had one of the 700r4 in my 86 and I had problems with that and that was just a 305 with an RV cam. Nothing special.
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The horrible compression ratio and crap heads are what’s hurting this set up. Putting a cam in it with heads that will only choke out any performance gain you would of gotten. Big block like to breathe and those heads are like you breathing threw a straw. A turbo would help. The low compression will work with a turbo and the air will be pushed threw. With a turbo you have good driving majors and power when you need it.
The sounds like a great idea. Have you done many BB turbo setups? I would just be worried with all that extra power a guy may have problems with the driveline. What's your experience with that? I am very interested.
as long as you don’t put a sissy 700r4 behind it and keep boost down to like 6 psi. Anything higher then that you may run into converter issues. You’d need one with an anti ballon game plate. If your gonna do it with a 10 bolt id go with an 89-91 Burb or Blazer rear axle and if 4x same years 10 bolt front axle too. They make carb kits to convert a Holley to be used as a blow threw carb. I wouldn’t use a Slobberjet or Edelturd.
I just bought a TH375 off a guy on Craigslist. Is that a good transmission? I had one of the 700r4 in my 86 and I had problems with that and that was just a 305 with an RV cam. Nothing special.
if you get a rainbow 700 the are a bit better but still crap a 375 middle of the road th400 is what you want. What you don’t want is a turd 305. Small blocks are for kids be a man and get a big block and quit throwing good money away.
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Good advice. I have big blocks in a couple of my rigs so I know what you mean.
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Good advice. I have big blocks in a couple of my rigs so I know what you mean.
well that’s a good thing. Small blocks are for learning and big blocks are for when you want to get serious.
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Swap in a 4.56? It will provide plenty of power with a stock setup. Of course, you'll only ever get 8 MPG again.
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No ones suggested an LS swap yet ?
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I found this a good thread. Especially ' jw454 ' info:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=10299.0