Pro Comp heads are installed.

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VonCramp

VonCramp

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I got the pro comp heads and intake, carb, and rockers installed on my 340... finally. The only problem I ran into was that the rockers didn't clear the valve springs. At all. I had to remove a lot of material from them. Which required removing the entire rockers and shafts multiple times to check clearances. The process took me two days just to get them to fit. I haven't driven the car yet because the valves aren't adjusted perfectly yet. However, let me say this car sounds insane now. The boosted compression and air gap style intake makes this car sound like a super stocker. The pro comp carb actually feels crisp when I push the throttle. There isn't really a combustion chamber to speak of. So, I guess that is why this thing sounds so nuts. The intake runners are huge compared to the x-heads. Overall, I feel like the $1275 I spent was worth it. I feel like a snob now because I scoff at the thought of stock parts. In fact I am selling my x-heads with adjustable rockers because I am never going back.
 
The rockers on mine had to be ground down as well , which rockers you using ?
 
jerry6 said:
The rockers on mine had to be ground down as well , which rockers you using ?
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I am using the blue pro comps with the roller tip. What a nightmare. Everytime I thought I was done, another one would grab a spring.
 
Are you running the full Procomp Topend Kit (Heads, Intake and Procomp carb)? If so I am doing the exactly install this weekend. What length push rods did you end up using?
 

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Thanatos340 said:
Are you running the full Procomp Topend Kit (Heads, Intake and Procomp carb)? If so I am doing the exactly install this weekend. What length push rods did you end up using?
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I have that exact same kit. Except I installed mine with the motor in the car. Not fun at all. I used the stock pushrods with the ball cup ends. When I bought my 340 X-heads they had adjustable rockers and the matching pushrods already. It is possible they are stock 273 push rods, but I don't know for sure. I would be happy to measure one and take a picture for you.
 
Thanks for the response. No need to measure, I know which ones you are referring to and have the same ones on the shelf. I am still debating using the Procomp rollers vs set of of old 273 adjustables I have. Sounds like the Procomps may be a much bigger pain to deal with when the 273`s may just bolt right up.

Another problem I have already ran into is that I will need to hog out the intake a bit for clearance as the carb butterfly can not open all the way. Did you zsee this problem too or just use a spacer under the carb?
 
Thanatos340 said:
Thanks for the response. No need to measure, I know which ones you are referring to and have the same ones on the shelf. I am still debating using the Procomp rollers vs set of of old 273 adjustables I have. Sounds like the Procomps may be a much bigger pain to deal with when the 273`s may just bolt right up.

Another problem I have already ran into is that I will need to hog out the intake a bit for clearance as the carb butterfly can not open all the way. Did you zsee this problem too or just use a spacer under the carb?
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I used that thick Mr.Gasket carb gasket under my carb. Carb seems to open all the way with no clearance issues. You haven't noticed any of your rockers hitting the top of the valve spring yet? As soon as I tightened the shaft down that the rockers ride on, I could tell some were hitting. Try moving the rockers back and forth. I am pretty sure you will notice they grab the top of valve spring. I used a die grinder to remove some material from mine. All said and done, I had to take material off every single rocker. It was very time consuming and having to bolt everything back together over and over was a pain in the ***. You will be surprised at how awesome the motor sounds though when done! Please let me know how it runs when you get it all buttoned up! Thanks!
 
Thanatos340 said:
Thanks for the response. No need to measure, I know which ones you are referring to and have the same ones on the shelf. I am still debating using the Procomp rollers vs set of of old 273 adjustables I have. Sounds like the Procomps may be a much bigger pain to deal with when the 273`s may just bolt right up. Another problem I have already ran into is that I will need to hog out the intake a bit for clearance as the carb butterfly can not open all the way. Did you zsee this problem too or just use a spacer under the carb?
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I'm using the old 273 rockers and with the Edelbrock heads all the rockers needed a bit O grinding , I'll take pics Friday to show where they needed grinding
 
For future reference, it's often possible to find beehive springs with similar open/closed specs to conventional springs. They pretty much eliminate the problem of rocker/retainer interference issues. It's a lighter assembly as well, mainly due to the retainer size. I've run them on my car for years.
 
Locomotion said:
For future reference, it's often possible to find beehive springs with similar open/closed specs to conventional springs. They pretty much eliminate the problem of rocker/retainer interference issues. It's a lighter assembly as well, mainly due to the retainer size. I've run them on my car for years.
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Yea, I totally overlooked that I could change the springs to beehives. I was so excited to finally have my new heads that I just wanted to get them bolted on.
 
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