Thornton design; a direct replacement for an exhaust manifold.
Our headers are polished 304 stainless steel, with a 1/2" thick steel flange, to prevent warping.
Please read the details below to ensure this is the correct purchase for you:
-Primary tubes are 1 5/8"
-Collector is 3" wide
-Exhaust flange is cut to accept a 2 1/4" or 2 1/2" exhaust.
-Adapter is needed to fit other sizes.
These headers will only fit big block Oldsmobiles with 455, 425, & 400 engines from 1965 to 1976. This excludes 1965-1970 B&C's because the steering boxes are rear mounted (towards the fire wall). If you can fit factory exhaust manifolds these headers will fit without any modifications. They fit a factory 4 speed manual transmission with clearence to the Z bar. It also mates up to a standard exhaust head pipe measuring 2 1/4" or 2 1/2". They will easily connect to down pipes for a big block Oldsmobile.
Please feel free to contact us with any questions!
Sold as a pair, with gaskets.
Oldsmobile Big Block Headers
Satisfaction guaranteed. All returns and exchanges are accepted within 30 days; no questions asked. The part must meet the following requirements:
Part is unused
Part is unaltered
Part is in original finish
Part to be shipped back with original packaging
We must be notified about the return so we can ensure a proper return/exchange process. We will send a call tag or return label via email. Shipping charges cannot be refunded, and customer pays return shipping.
Returns are subject to restocking fees if not returned in original packaging or deemed poorly repackaged. Any and all fees and duties associated with your purchase, are your responsibily.