Well this is my 2nd 400 I have owned.I sold my first to a buddy and it is still in his garage doing nothing.And probably will remain there until I offer to buy it back.


Here is what I bought.


A pretty fresh 406.Has about 700 miles since rebuilt.It was in a buddies nova.(not originally)He traded it for a blazer so he took the 400 out and swapped a 350 in.


The casting # on the block is 3951511.I looked it up and it is supposed to be a 4 bolt main.I heard that the 400 4 bolts mains where weaker than the 2 bolts.Due to the lack of material in the block where the main bolts thread into Is this true?Do I have anything to worry about?


The heads are casting # 3973493.How do these heads perform.When I looked up the block it said something like 220hp from the factory.So I guess they flow alright.I plan on having 2.02/1.60 valves put in them along with screw in studs and guideplates.


The motor also has a torquer 2 intake and 1406 edelbrock carb.(600cfm electric choke)Along with a non cc HEI distrubitor.Also has the water pump,altenator and a flex fan to.)

It has an RV cam in it.I have heard alot of people talk about an RV cam.What it is?I am going to swap cam.(gonna go with something like the comp cams cam with 226/234 duration @ .050.And .480/.498 lift.I know this is a mild cam.But it is to mild.The motor is going in a 4000lb truck with a 3000 stall convertor and 3:90 rear gears.



Do you think I got a good deal.I paid 500 bucks for it.And do I have a good starting point for 450hp/450 foot pounds?



Thanks.

 

That's not too bad of a deal, if you can re-use the pistons and everything.

I wouldn't worry too much about the 2-bolt / 4-bolt thing, for what it appears you are doing. It will be fine. Something else will break long before you reach the point where the block becomes an issue. Be more concerned about what rod bolts it has in it.

Lose the heads, they are the stock 400 heads, major smogger garbage. 220 HP is pretty pitiful for a 400, just barely over ½ HP per cu in. Don't waste money on studs and valves and all that for those, it's basically polishing a turd, if you're going to spend money on heads, start with better castings. If the pistons are stock 400 ones, with deep dishes, you should look for some kind of 64cc heads.

Also lose that intake. That carb is too small; you need a 750. Get a Holley with mechanical secondaries.

A set of Vortec heads and a Performer RPM would match that cam and converter and gear fairly well, except that you'd need to get the valve guides cut down.

That combo should put you up close to 400 HP, and more than 450 ft-lbs.

 

Thanks for the info.

I had read somewhere that there was a 180hp 400 also.So I thought maybe these where a little better head.

I have a set of 906 vortecs I guess I could have a shop drill the steam holes,screw in studs,1.94/1.60 valves.No guideplates needed because of the self aligning rockers right?Also an airgap intake and 750 edelbrock.I have a 1406 on my daily driver and I like it alot.I like edelbrock.I am horrible with carbs.Even though I no my edelbrock isn't perfect tuned.It feels like it is pretty close to it.


I plan on using the torquer 2 and the 1406 off the 400 on a 350 I am building.

 

No, not a better head at all..... just an earlier HP "rating".