350/455 conversion

F

fastskylark

Guest
Ok I am having to problems. I am converting my 71 Skylark from a 350 to a 455. My first problem is with the headers i am installing. They are poston headers for a 455. I am having trouble getting them to fit. Any suggestions on getting them to fit would be great. My second problem is with the ignition. I need to convert the existing ignition from points to hei. I have no clue how to do this. Any links or an easy way to do this would be awesome. Thanks for the help.
 
Never had Poston headers, but I constantly read about people having problems trying to get them to fit. Be prepared to use a hammer on them.

For the HEI info, there are very good diagrams that MSD publishes on their website for using their 6A boxes and billet distributors with various generic ignition components. Even if you don't use their products, those diagrams are conceptually worthwhile for any ignition system, and are found in their online product manuals.
 
pertronix is a good alternative to msd. allows you to maintain oem appearance if that is important to you.
 
If the motor is already in the car, you might have to lift it back out. I know with the headers in my car (not made by Poston but probably shaped kinda similar), the only way to install/remove the headers is with the engine lifted. Remember, this is a "big" block...

If you have already done all of the wiring, etc., then you might be able to get away with just disconnecting the motor mounts and tranny mount, and lifting the engine-tranny a few inches, but still in the car. I have done this to get the oil pan off without removing the motor.

-Bob Cunningham
 
The engine is currently out. I have had it in twice before but i have taken it out 2 times for other reasons. Should i connect the Headers to the engine then put it in or set them in the engine bay?
 
Usually your best bet if the engine is already out is to set them in the engine bay. You may have to bang em pretty good with a hammer in order to get them to fit. Secondly, do you have new motor mounts? Sagging motor mounts are a sure proof way to make headers not fit.
 
Yeah, I would put them in there loosely. Then when you drop the motor in, stop about 1" above the motor mounts and bolt the headers onto the heads. Then, drop the motor onto the motor mounts.

-Bob C.
 
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