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update - 1970 240 that won't go 85mph

282 Views 3 Replies 4 Participants Last post by  Tony D
I think someone else is having the same problem I am. My car was sluggish and wasn't very fast, this is my first z so I wasn't sure if it was normal.

I did a compression check, between 90 and 100 in all cylinders. I put some oil in and the compression went up to about 115.

yanked the head off, much easier than expected. gasket was cracked up front but no signs of being worn around cylinders. the 2 middle cylinders had a lot of carbon on pistons.

I went to the junk yard and they have a couple 280 engines for about $350. Should I put my head and SU's on the 280 block? I thought this may be the least expensive way to get back on the road.

any opinions on what I should do? updated engine, rebuild the 240, use my head on a newer block? There is a 1983 280 in the local paper that is supposed run great but has some rear end damage. they want $1000.

I want a daily driver that will spin the tires, nothing dramatic. any thoughts would be appreciated.


Peter Schmid
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If you have a 1970 model with the original motor I would suggest to check cylinders for scoring and take the head apart, new valve seals, check the valve guides, of course all cleaning and lap the valves. Make surre to keep all the valvetrain components in order! so they go back into the exact same location where they came out of. Bottom ends on theses motors are VERY stout. What is the production month?
Put in larger valves and you will have a much faster car than before. It will not be a rever like the 240 but the low end will have alot more power. You will probably need to use premium gas because the comp. ratio will go up a bit.

I would ask "did you block the throttle wide open during the compression check?"

Those numbers while low, should not affect the top speed of the vehicle one bit. I have had plenty of 240's with "low compression" still easily pull 104 in third gear.

I would still look closely at electronics. What you have found is a non-starter, and you are now well on the path of shotgunning a problem that didn't exist...

Did you do the tune up yet? (SH)
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