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The 2-Stroke Garage => Turning Wrenches => Topic started by: hoffkurt on April 20, 2022, 04:29:21 PM

Title: RD350 motor with RD400 heads.
Post by: hoffkurt on April 20, 2022, 04:29:21 PM
This is a motor I'm looking to put back on the street. I was told it was used for flat track racing. Should I put 350 heads back on it or keep the 400 heads? Any pros or cons with the 400 heads? Thanks!!
Title: Re: RD350 motor with RD400 heads.
Post by: m in sc on April 20, 2022, 05:28:18 PM
were the 400 heads modified for the 350 motor?
Title: Re: RD350 motor with RD400 heads.
Post by: hoffkurt on April 21, 2022, 08:46:26 AM
I'm not sure of the history but my understanding is it was a performance upgrade that used to be done. Was wondering if anyone had any experience with it. Any old time racers still here?
Title: Re: RD350 motor with RD400 heads.
Post by: AAAltered on April 22, 2022, 10:16:15 AM
Not a racer, but here's my experience.
I was gifted a set of DG400 heads.  The domes showed signs of a blowup.

They were sent to Scott Clough Racing, SCR.  You can find him.

Scott did a fair amount of work to them.  Reshaping and resizing the dome, cut the decking ( wrong term, I know) and overall set them up for a 350 on modern gasoline.  He offers an option to O-Ring them also, mine are not and run a standard 350 copper gasket. 

Point is even if those heads were some sort of trick in the old days, there's PLENTY of reasons to get them, or any head reworked these days...

Head 1
(https://i.ibb.co/qgcvtjX/C6755-AED-5484-40-C4-A38-F-17857-EC99-F39.jpg)

Head 2
(https://i.ibb.co/s5dzyKf/3-BA87145-B54-B-40-A5-9514-E6425667187-D.jpg)

Both heads restamped and cut by Scott
(https://i.ibb.co/LtzfSCY/26-FAA1-C2-9-CD6-44-F8-8-BC0-5362776818-B3.jpg)