Thread: 75 Impala build

Tweet

I'm doing a engine swap I had this Chev 350 engine in a Buick Regal. Always had plans on getting a nice chevy to put it in. Okay casting numbers on this engine is 3970010. It has stock heads, Comp roller rockers, had a comp cam but just switched to lunati cam 500 lift, airgap intake, edelbrock 600 carb, flat top pistons, full length headers which are giving me a problem, 3.73 gears, going to get an electric fan. When we swapped the engine into this impala it was running pretty fine besides a little lifter tap, but changed cam to a lunati cam and lifters and during the break-in no tapping but running to lean. Guy came over and said it needs to get more gas and it will be fine. So we had to stop the break in of the engine. It was running to hot because the headers were glowing red hot it turned the headers from black to grayish white color. Talked to the guy who came over and said its running to lean and he said changing the jets to give it more gas will do the trick. also we were trying to break it in with no fan shroud. We rand it a couple minutes about 4 times and it was overheating and the last time it shot out all the radiator fluid. I have a 180 degree thermastat and was told to get a 160dg, and i am going to get an electric fan some header wrap to save my plugs because it burned a few and am going to get an edelbrock calibration kit part number 1487 that is supposed to give it more gas since it is running so lean because i can't afford to get another carb right now. Hoping that doing all this will have it running good and the guy who is installing my engine can go ahead with the break in tomorrow. Also its a 350 tranny with 1800 or 2000 stall i really can't remember. What do u guys think about my set up. The guy said it should put out around 310 horses with this set up. Also what do u guys think about it running so lean now was it the changing of the cam? Before I changed the cam the timing was set to -3 i think to run on 87-89 gas if i wanted to The guy who is doing the engine now said he was going to keep it that way although he said it should be at -0. Let me know what u experts think about all this! I guess this may be a lot to read but I'm trying to let u all get a good understanding of what is going on. I'm no engine builder but i do want to learn. Thanks guys!

Well, the chebbie guys will be along, but too me it sounds like the timing needs to be advanced. Timing retarded will really heat up an engine......

The guy thats insalling the engine wasn't sure whether I had flat top pistons or forged so he said he did want to do it if they were forged. But they are supposed to be flat top hyper. So what do u think about my setup with the voodoo cam?

any feed back guys.

I think I'd find out for sure what the pistons are first thing... You didn't say what you are running for heads, or what has been done to them. A camshaft is important for performance, but without heads that will match it's performance level the cam won't be able to work to it's full potential.....

Its got stock heads. Pretty sure they are flat top pistons because the guy who built the engine said they are

Check what # heads you have the 1974 and Later 350s had 882 or 624 heads . The the 882 heads if not cracked can be ported to make more HP . The 624 heads are the thinest cast 350 heads ever made best to change them . Now the 3970010 Block was used from 1969-80 you may have a good set of heads on there . The best 76cc GM heads are the 487 or 993 castings they are 76cc with 1.94in 1.50ex valves and a thicker casting .

I agree with Dave on the timing. The glowing headers suggest to me that the timing is retarded. I have seen this happen several times on new engine start up. If you are following cam break in procedure to run the engine at 1800-2000 rpm for 30 minutes, make sure your timeing is in the 32-35 degrees total timing at that RPM. if you don't have a way to do that with your timing light or a tape on your balancer then set it real quick at idle at about 6 degrees then make sure it is advancing as you rev the motor up. What you think is a lean condition may not be that at all, just late timing.

It's something to check before trying to dump extra fuel in there.

Pat

Thanks guys were also checking the fuel filter and it seems to be a little clogged. So im gonna get a new one and a bigger one because were thinking that one may be a little to small he says he has changed the size of a line before and it cut out a similar problem.I also may try getting a new fuel pump maybe one that pushes 110 gallons per hour because right now I have stock pump. The timing is retarded to -3, we were thinking they guy who built it the engine did it in order to be able to run on 87 or 89 gas, so we just left it that way.

It's going to keep overheating at -3!!!!!! Get the timing set to 8 to 10 degrees ADVANCED!!!!! Fuel probably isn't even the problem, retarded timing will make the engine overheat.

I went and got an electric fan and the guy who is doing the engine says it probably needs a bigger carb. Its a edelb. 600 model 1406 electric choke. He went and got the calibration kit and jet it out and that helped kool it down a little so instead of having about 4 or 5 header tubes glowing red hot we got it down to one that is still glowing. I'm trying to get down to exactly what the exact problem is and i need to know do i need a bigger carburetor like a 650 or does he need to adjust this timing???

Well guys went and checked it out today and I guess he got the carb all jetted out the way it was supposed to be and everything seems to be fine car runs good has a lot of power and no more glowing headers. I still just wonder how much better will it run if he were to set the timing chain on zero so he would be able to advance it. what do you guys think?? Also what do u think about getting a 650 carb or if this one is jetted out already is it alright like it is? and what about a carb spacer I here that they can act as if u had a bigger carb but u just have to try and see if they work out with your combo so i figure with the calibration kit and jets i added to the 600 carb and a spacer i might be at 650 cfms. Tell me what u think.

Actually the 600 carb is overkill for a 350 anyway, so if you want a 650 or a 750 go for it. Don't think either will hurt anything other than your gas budget.

Okay now I've been driving the car and at idle the temp get at around 190 deg. after driving for about 20 min. while driving it stays around 160 deg. But this is without a shroud but I have an electric fan. Will the shround Kill this problem? Also In the car the temperature light is flashing on even at aroung 160 degrees?

as long as the engine dosn't rise to 225* it will be fine.. ideally you should have a 180* thermostat, the motor should get to 215-225* but no hotter at idle, and around 180-195* cruising...

BTW, I think you need a new builder. the valve timing set to -3* on a street engine is no good.. only run str8 up on a street engine. that will probably cause you problems.