Sounds like a similar mindset or build. I swapped mine in back in 2004, not much has changed since. I didn't put it together myself but it has flat top pistons, Hooker 2050's and my Q-Jet by Cliff Ruggles. Just Vortec heads, I have the cam specs somewhere, have to dig it up. With the 200-4r and 3.42's I was getting lower to almost mid 20's on all highway driving when I last checked, that was awhile ago though but nothing really has changed much. There is a person on montecarloss.com who burns chips and was selling replicated ZZ4 versions, actually might of even been two people doing this. Hooker 2050's pop up used once in awhile I've seen, really glad I have them on both of my cars, they aren't robbing any power even though I'm not really emissions friendly and have since eliminated the AIR tubes on both due to them breaking off at the primary tubes on a couple cylinders on each car after so many years. Since not hooked up and they needed to get welded just removed them and welded the holes shut/re-coated them.
305 to 350 CCC swap
- Thread starter Jeff Eller
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Took the 1989 truck 350 short block I bought this week apart. Got the crank, rods and Pistons, cam and lifters and freeze plugs out of it. Going to take the cam bearings out tomorrow evening and the block will be ready for inspection and cleaning and machining. Thanks for everyone's support and help.
Disclaimer: I am talking Olds 307 to big block here. Not experienced with Chevy conversions. But, there should not be significant differences between 305/307 ECMs.
You will be surprised how much the ECM will tolerate. Just going 305 to 355 in of itself will likely not even matter. A friend went to a stock smog motor 455 with the 307 CCC and it worked fine other than needing to tweak the idle bleeds and swap the secondary rods. Your 264 cam selection will be right at the hairy edge of causing off idle light throttle problems and problems with lean burn mode when in 4th and lock up using stock code. And, the CCC should work OK though you might want to experiment with different secondary metering rods when you are open loop with your foot in the fan running more cubes. The ECM won't even care or know about that. The 355 might like a step or two smaller metering rods. The car may well idle fine without primary side CCC mods just going to the 355. I want to say the stock idle bleeds are just .042 but it's been 10 years. Worst case you might need to take those out a few thousandths to accommodate 50 more cubes but I doubt it. I think the 262 cam would be completely safe on stock code. I am not familiar with aftermarket chips other than the only one I could find for the 442's [9] engine, what Hyperchip Hypertech [?? forget the company], did absolutely nothing and I mean NOTHING and might well have been a stock chip in wolf's clothing.
With custom code, I am about two steps higher cam shaft than your desired 264 in my big block conversion though it came from Mondello ~ the JM-20-22. We never could quite dial in the JM-22-25-10 despite 3 tries. Now, it ran and perhaps ran good enough for many but I was lucky that I was working with a friend that was even more anal than I am about how smooth the engine performs and we both actually cared about fuel efficiency so we wanted to keep lean burn even on the big block. I like to be able to make it at least to the next pee stop before I have to fill up . . . thank you very much! And, with my bladder anyway,18-20mpg will get me there. We would have had to just punt lean burn completely with the bigger cam though which some aftermarket chips do and the light throttle was just a tad rough. But, the 3rd time was the charm using the JM-20-22 and it is a GREAT street cam for the big block.
Now, on the big block I had to dual up my PCV valves to solve an off idle light throttle problem with the PCV system. You should not have to do that. I take filtered air clear down into the crankcase through the oil filler tube and then evacuate both valve covers. Worked really slick to solve our light throttle PCV problem with the single valve wanting to oscillate plus it does a more efficient job of evacuating the block anyway [tear apart a high mileage motor and look at the air inlet valve cover ~ sludge city]. Other mods I had to do were to take the idle bleeds out to .056 and I had to add .075 air holes to the primary blades to get the big block to idle and I went with '70 W30 secondary metering rods which work great.
Good luck with your project . . .
You will be surprised how much the ECM will tolerate. Just going 305 to 355 in of itself will likely not even matter. A friend went to a stock smog motor 455 with the 307 CCC and it worked fine other than needing to tweak the idle bleeds and swap the secondary rods. Your 264 cam selection will be right at the hairy edge of causing off idle light throttle problems and problems with lean burn mode when in 4th and lock up using stock code. And, the CCC should work OK though you might want to experiment with different secondary metering rods when you are open loop with your foot in the fan running more cubes. The ECM won't even care or know about that. The 355 might like a step or two smaller metering rods. The car may well idle fine without primary side CCC mods just going to the 355. I want to say the stock idle bleeds are just .042 but it's been 10 years. Worst case you might need to take those out a few thousandths to accommodate 50 more cubes but I doubt it. I think the 262 cam would be completely safe on stock code. I am not familiar with aftermarket chips other than the only one I could find for the 442's [9] engine, what Hyperchip Hypertech [?? forget the company], did absolutely nothing and I mean NOTHING and might well have been a stock chip in wolf's clothing.
With custom code, I am about two steps higher cam shaft than your desired 264 in my big block conversion though it came from Mondello ~ the JM-20-22. We never could quite dial in the JM-22-25-10 despite 3 tries. Now, it ran and perhaps ran good enough for many but I was lucky that I was working with a friend that was even more anal than I am about how smooth the engine performs and we both actually cared about fuel efficiency so we wanted to keep lean burn even on the big block. I like to be able to make it at least to the next pee stop before I have to fill up . . . thank you very much! And, with my bladder anyway,18-20mpg will get me there. We would have had to just punt lean burn completely with the bigger cam though which some aftermarket chips do and the light throttle was just a tad rough. But, the 3rd time was the charm using the JM-20-22 and it is a GREAT street cam for the big block.
Now, on the big block I had to dual up my PCV valves to solve an off idle light throttle problem with the PCV system. You should not have to do that. I take filtered air clear down into the crankcase through the oil filler tube and then evacuate both valve covers. Worked really slick to solve our light throttle PCV problem with the single valve wanting to oscillate plus it does a more efficient job of evacuating the block anyway [tear apart a high mileage motor and look at the air inlet valve cover ~ sludge city]. Other mods I had to do were to take the idle bleeds out to .056 and I had to add .075 air holes to the primary blades to get the big block to idle and I went with '70 W30 secondary metering rods which work great.
Good luck with your project . . .
Thank you very much for the information. I will refer back to your thread and others as I continue my journey.
What you have done is very impressive, awesome power and mileage with a carb. Yes, you started with a Vin 9 set up, which is better, most have no issue using compared to the Vin Y. Doesn't your swirl port computer have a retarded amount of advance, like nearly 60 degrees? The pre 85 ones have less advance, supposedly. From what I have seen with the sbc TBI set ups, 9 to 1 with a tiny cam, it has a very lazy timing curve. I advanced base timing 20 degrees, still only got 50 or so degrees part throttle. At stock 0, it wouldn't idle worth a dam and back fire on my Olds 350. I would bet the Monte SS ECM with a 9.5 to 1 305 has a similar lazy curve to prevent detonation, which is why, along with the better carb calibration, is why they would be desirable.
I think Chevy CCC systems had knock sensors before Olds CCC got them. This allowed Chevy to run a little more sharp advance curves, especially with the L69 and ZZ4 Proms.
Well, don't want to dump on the OP's thread here to discuss my project much . . . but I don't know what to tell you? My big block actually ran on the factory code without the nonsense you have described. Now, granted, not very well, but it ran. And, Kevin ran his 455 smog motor off a Y ECM with virtually the same carb mods. Without mods to the primary side of the carb yet, I had to have the idle screw so far in that the primaries were cracked open just to get it to idle. But, to get started modding the code, I went and drove it on factory code just to get a laptop dump on where we were at with it? Light throttle was horribly rough but no popping, backfiring, etc as you have described. And, when it tried to go into lean burn on the H/W, that instantly went ping city on the factory code so just long enough to get data and I popped it down into third and went back home to send Kevin the dump. The first chip was a lot better and I had modded the primary side of the carb and had gotten my new secondary rods by the time I had his first chip. [Yes, I know the secondary rods have nothing to do with closed loop . . .] We went through just 3 chips to get where it's at today. Truthfully, I was happy with chip 2 but Kevin wasn't. And, he was right, he got it even better along with the pcv mod I mentioned earlier.
Saying "retarded amount of advance, like 60 degrees"? I assume you mean it's "retarded" [or stupid] to have that much advance as opposed to "retarded timing"? Hey we still have like [sorry, it's been over 10 years] but I'm pretty sure 63 maybe 64 degrees max advance during lean burn in 4th and lock up but just had to richen the mixture slightly for the additional cubes and CR which took me from 23-25mpg with the 307 down to just 18-20mpg but that ain't bad for a big block with a CCC on top. Beyond that, the thing runs just fuel injection snappy . . . though frankly I've had it scattered long enough I've almost forgotten what it's like to drive . . . Almost!
EDIT: And, you are correct, I did not and do not have a knock sensor.
Saying "retarded amount of advance, like 60 degrees"? I assume you mean it's "retarded" [or stupid] to have that much advance as opposed to "retarded timing"? Hey we still have like [sorry, it's been over 10 years] but I'm pretty sure 63 maybe 64 degrees max advance during lean burn in 4th and lock up but just had to richen the mixture slightly for the additional cubes and CR which took me from 23-25mpg with the 307 down to just 18-20mpg but that ain't bad for a big block with a CCC on top. Beyond that, the thing runs just fuel injection snappy . . . though frankly I've had it scattered long enough I've almost forgotten what it's like to drive . . . Almost!
EDIT: And, you are correct, I did not and do not have a knock sensor.
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One last thing I got away from carbs went to EFI Firtec best thing I ever did no more cold blooded starts to warm engine. I don't use the puter any longer. Changed out the distributor & intake. My 305 HO crapped out it was a weakling compared to the 350 I now have. I run A/C well all changed to 134 with all new parts for the A/C. Summit has the EFI set up instant acceleration, instant start up no more sorry computer controlled quadrajet, prior to the swap was running a Holly 670 ddl pump good carb but still a carb. Holly makes a EFI set up called the Sniper. Summit has them. Rebuilding a 65 T-Bird will be using that set up on the BB 390 as I said no more carbs for me just personal performance!
Just a suggestion my 350 isn't stock but it's not a 383 hi performer either. It has the stock 373 rear gear I want to change to a 342 or 323 since I don't race any longer. Need to find a 83-84 MC SS my preference. But get away from the brain if possible go EFI u will be glad u did I believe. Want to need to chip up either oh yes went to a HEI one wire distributor with internal coil 50,000 volt
Hope this helps if not interested food for thought later on. Good luck with ur change over.
Just a suggestion my 350 isn't stock but it's not a 383 hi performer either. It has the stock 373 rear gear I want to change to a 342 or 323 since I don't race any longer. Need to find a 83-84 MC SS my preference. But get away from the brain if possible go EFI u will be glad u did I believe. Want to need to chip up either oh yes went to a HEI one wire distributor with internal coil 50,000 volt
Hope this helps if not interested food for thought later on. Good luck with ur change over.
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