isosceles

weird stuff. Last summer, I had a comp 270H installed. The L48 didn't sound any different from stock unless it was cold. It idled like glug glug glug.

Now idling at 750-800 out of gear it's a tad rumpity. The difference? The MSD setup I was using when the 383 was in the car, electric fuel pump and the carb off the 383, rejetted, of course.


Temps start climbing a bit in traffic where the 383 stayed cool. Same cooling system. I wonder if that stupid plug I dropped is blocking water flow somewhere? I'll have to look at the radiator with the cap off. Cools right back down when I start moving again. I suppose it might be air still in the system. The overflow tank was dry yesterday and the rad was 1/2 gal low.

page62

It could also be your water pump is going bad...

bobs77vet

i don't see how it can be helping any....it may even change position with bumps...

isosceles

well, water is flowing very well through the radiator, spraying out of the top tubes. The radiator is less than a year old and a 4 core.I tried bumping the timing up a few degrees, can't advance any further or it pings on acceleration (36 in before 3000). Why does this low compression motor run so much hotter than my 383? I even used the same water pump AND thermostat! Everything about the cooling system is the exact same except the block and heads.

bobs77vet

well except for the plug floating around.... i wonder if the block can have a different resistance throwing off the sender?

isosceles

True!

This motor used to run hot on the highway until I changed the radiator. Now it runs cooler on the highway. Could need an ever richer primary jet. Think I'll go pull a plug.


edit:Pulled number 4, which I beleive is supposed to be a bit leaner along with #3 than the rest. It was tan. These are AC rapid fires with I think will run a few shades light anyway.

Maybe there is just more crud in the block and heads than on the 383.

BSeery

How about the lower radiator hose? Is it collapsing at higher RPM's ?