need help and some info on engine build

[mikey2409]

I'm currently rebuild a 350 with a 400 crank and running into issue not having a clue that this engine had a big crank so heres some help I'm needing to determine and fix my problem first I know I need to build the top end with a different cam which means need to change springs lifters and so on and my next thing is I'm going to be running a th350 so do I have to upgrade my flex plate to a 400 or can the 350 flexplate work beside up grading the torque converter to a higher stall

[rickpilgrim]

When using the 400 crank in the 350 block you need to use the 400 balancer and flexplate as the 400 is externally balanced with those 2 things and all other sbc engines are internally balanced.
The 1974 400 I have has the flex plate drilled for both the small(th350) and large (th400) patterns as are most I have seen so that should not be a problem.
Cam lifter and springs should be matched and hardened push rods are always a good idea. All I will say about cams is if a truck engine 218@.050 is about the biggest I go to preserve good street manners and stoplight to stoplight driving. Above that like in my 82 355 crew cab which has a 221@.050 cam you lose power below 1800 rpm but when you hit 2400 it's like you flipped a switch and added 200hp. That's great for highway but around town not so good. With today's oils a roller cam would be nice so you don't have to add zinc supplements all the time.
Unless your going to the track 2200-2400 stall is the most I like on a daily driver.
I used to run a 2800-3000 stall in my 355v8 Monza Town Coupe and while on Saturday Nite it was great but Monday-Friday it left a lot to be desired. These days I have L60E and L80E which are nice as you can get stall and lockup at the same time.
Good Luck on your build

[mikey2409]

the heads it has are intermidiate hi performance 350 heads the valves are 1.94 / 1.50 after reading Rick's post I'm thinking a cam kit is the best way to go

[rickpilgrim]

If looking for a good idea on what cam you like try comp cams camquest program on the compatition cams website. You just enter all your engine and vehicle data and hit the recommend button and it will give you several choices to choose from and even give you a dyno result with it. Even if you don't like comp cams stuff you can use it to find a profile you like, write it down and go close if not exact with your favorite cam company.
It's really usefull if you have plans for future power adders as you can see what different heads,compression, manifolds ,headers bigger valves etc will do for your combination.
Try it and go from there with you build, it will point you in the right direction

[King Cary]

As rickpilgrim said it has to have the 400 balancer and fly wheel but if you haven't figure it out yet the block will have to be clearanced to make room for the throws on that crank.

[King Cary]

And also, if you are planning on adding more power later I would go with a set of heads that have 2.02 valves and a good intake is pretty cheap for a smallblock.

[mikey2409]

So what type of vehicles would I find those heads on cause right now I have the oe heads wit stamping of 333882 heads which from my understanding are notorious for cracking on a stamped factory engine code of 3970010 if that helps

[rickpilgrim]

Those 882 heads were about the best of the 74-80 smog era heads in terms of port flow.

That being said 2.02/1.60 valves don't necessarily mean good performing head for your motor. One of the best factory heads of late are the 96-2000 vortec 350 engine found on any 96 and newer 350. They are worth 30-40hp over your 882 heads and even summit racing sells them. You do need to get the rocker arms with them and you do need a vortec carb style intake manifold but the right cam and vortec heads put you 60-70 hp over the 882 heads and stock cam. I have some good 2.02 1.60 heads on I 350 and vortec heads on another and the vortec needs less cam/fuel than the 2.02/1.60 heads for the same power .
Good luck on the build

[King Cary]

Yes, mikey2409.. I totally agree with rickpilgrim but I didn't know your budget for your engine build and the cost of heads can be costly. Everyone has older style 350 heads laying around that you can pick up for cheap. Newer heads and less cam or older style head and a little more cam but don't over cam, that will cause you other issues.

[mikey2409]

so I can basically pull these heads off any vehicle or buy them between the years that was posted with any or to no modifications besides the vortec intake