Small Block & Big Block Chevy Specific Mouse & Rat Motor Discussion & Conversions

403 olds motor

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Old Oct 7, 2007 | 08:02 PM
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Default 403 olds motor

does anyone know anything about this motor? like can i fit a 350 stroker crank in it? or anything to mod it?
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Old Oct 8, 2007 | 05:53 PM
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Look into Mondello Performance. When I had mine I was looking at putting the Olds 455 Edelbrock heads on with a Performer RPM manifold and a custom cam. These are great motors and most of the time you can get them for free or close to it since people don't like messing with them. Tiny stroke and huge bore is a nice combo.
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Old Oct 8, 2007 | 06:57 PM
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yea, ive looked everywhere, and i cant find much info on them, i was hoping i could get some help here, all ive seen people do on them are either edlebrock heads, or 1970-73 350 heads because of the higher compression, ive had the heads i have on it already port matched to an edlebrock performer manifold, and a compcam installed, and i still didnt feel any difference..... the most ive seen them put out is 325hp.... bearly enuff to keep up with 4th gen f-bodies
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Old Oct 8, 2007 | 07:00 PM
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well this engine i have is in a 79 pontiac trans am, im starting to think of just swaping it out with a real pontiac 400...... anyone wanna buy an 0lds 403? lol
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Old Oct 8, 2007 | 10:09 PM
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The aftermarket for them isn't there so if you expect it to be like a Chevy then in for some frustration. A motor is a motor, no secret, get as much air as you can into the motor and with the big *** 4.351 bore you can use Big Block heads which is great. I'm guessing that you have the 4A heads which are pathetic and need to be worked over extensively if you are going to keep them, port matching does nothing other than look pretty on the old smog heads. You are going to have to address the compression ratio first. Stock they came with 7.9:1 IIRC. I had one rebuilt and bumped the CR up to 8.5 with only a small cam and I made 250/325 to the ground through a TH350. It was easy to keep up with 4th gens. It's not hard to make power with these motors, just takes a little effort. You can't just throw parts at them like a Chevy.

http://www.popularhotrodding.com/tec...mobile_engine/
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Old Oct 8, 2007 | 10:55 PM
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cool thanks for the info
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Old Oct 9, 2007 | 05:44 PM
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Where are you located? If you want to still go the Pontiac route and want to give away the motor I'll take it off your hands if you're close. Something else to look into is a Olds 455, everything will swap over from your 403.
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Old Oct 9, 2007 | 06:30 PM
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LOL ... u need #5 heads from a 68-70 olds 350 ... youll need just a little work to make em fit but damn its worth it ... See below
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Old Oct 9, 2007 | 06:31 PM
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http://www.texastransams.com/article...03_article.htm

.. i can supply some pics if ya need em
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Old Oct 10, 2007 | 06:01 AM
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Not to jack your thread but I am tring to put a 455 olds in my 81 TA. Any one know where to get motor mounts or what mounts I need. Currently have a chevy 350.
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Old Oct 10, 2007 | 06:43 AM
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Need the mounts out of a 403 T/A if you can find them. Texas Trans Ams could probably help you, just tell him what you are doing and he will get it for you. Link posted earlier.
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Old Oct 11, 2007 | 04:15 PM
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Look on Real Olds Power http://72.22.90.30/phpBB2/index.php Don't give your money to mondello, he is not running his company anymore. Alot of people have been getting ripped of by them. As for motor mounts in the T/A, Find a T/A that came with a 403 and you could use them.Thats what I did with my 79 that had a 455 olds. The sbo mounts will make your engine sit about an inch higher than bbo mounts. With a performer manifoldmy carb sat about an inch from the shaker opening. Look on the site I know there are guy s that have 455s in their t/a.
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Old Nov 1, 2007 | 10:46 AM
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Wonder if these mounts are what I need to put the 455 Olds in my Trans Am?

http://cgi.ebay.com/ebaymotors/ws/eB...TQ:MOTORS:1123
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