[tremo]

I'm building a RA-IV 400ci to replace the old, original 350ci in my '69 Custom S. My funds are getting low so new headers will have to wait.

Will my 350ci exhaust manifolds on #47 heads bolt right up to the #16 heads on my 400ci? I'm hoping they will as this would get me by until the bank account heals. If not, I'll need to scrounge for some stock 400ci manifolds.

Thanks!

Jim.

[b-man]

The 350, 400 and 455 D-port exhaust manifolds are the same if they are made to fit a certain chassis. No difference in fit or flow, same goes for 326, 389 and 421 engines.

[tremo]

Thanks b-man. I found a pic of my #16 heads (the motor is at the shop) and I now see the bolt patterns are the same. Since I plan to use my 350ci manifolds from my existing A-body chassis on the new 400ci, it looks like I don't need to worry about "...if they are made to fit a certain chassis.".

Now all I need to do is get them off the old 350!

Thanks again!

Jim.

[TJH]

Just curious- Since what made a RAIV a RAIV was the heads, and since you are NOT using RAIV round-port castings, why do you think it is a RAIV?
Since you have D-ports, ANY D-port manifold will bolt up. In fact, those same manifolds that you have, were used on the non-RA A-bodies.
If you're running 1973-74 16's, your CR will be in the toilet, and you'll need round-port manifolds but, since they're then SD455 heads, you could probably sell them and buy some E-heads).

[tremo]

Thanks for the addt'l confirmation on the manifolds bolting up.

Yeah, granted, the missing element is the round-port heads (hard to find, etc). Otherwise everything else is RA-IV spec. The heads are '70 D-port, small chamber (72cc), small valve (1.96/1.66) converted to large valve (2.11/1.77). Per WallaceRacing.Com's Head Search:

1970 400 290HP 16 (sm valve) 1.96/1.66 10 c.r.

With the small chambers, proper head gaskets, etc., we estimate the CR will be around ~10.75:1.

Seee-ya,

Jim.

Originally Posted by TJH

Just curious- Since what made a RAIV a RAIV was the heads, and since you are NOT using RAIV round-port castings, why do you think it is a RAIV?
Since you have D-ports, ANY D-port manifold will bolt up. In fact, those same manifolds that you have, were used on the non-RA A-bodies.
If you're running 1973-74 16's, your CR will be in the toilet, and you'll need round-port manifolds but, since they're then SD455 heads, you could probably sell them and buy some E-heads).