[cokeman277296]

I got me a 400 sb bored .040 over. I went with 882 heads with 2.02/1.60 heads with flat top pistons. I should have 10:1 comp. The problem im having is whick cam and carb. to get. I've been looking at the comp extrem energy cams, the xe268h to be exact, but I cant make my mind. And I cant decide on either a 750 or a 800 carb. I want something with alot of torque and decent HP. It going in a 83 C10 with a 350 turbo tranny with a 3.42 gear with eaton positive traction. Whatcha think?

 

[MI2600]

I'm running the XE268 in my 406, 10:1 compression, headers, with the same rear gear. It's a good combination. Idles nice, not real lumpy but you can definitely detect that it's not a stocker.

I used an Edelbrock 750. I had to use an Edelbrock intake because of the Vortec heads.

 

[rifraf]

Since you seem to be more concerned with the bottom end,smaller would be the choice for me,it will be easier to set up for jets and such,also,if you decide on that cam I would also entertain the thought of a yet smaller carb,it will really help your low end response,a 650 will pull you near the limits of that cam I would think,the sacrifice of tunability and response may not be worth the small gain in HP way up high where you rarely ever are. I would scope out a Barry Grant speed demon 650,they seem to flow more air than other 650s,better yet,call them up and voice your concerns,they are real helpful,and they have great carbs for a great price.

 

[Tech @ BG]

Your combination could go either 650 or 750. A 650 will give you better torque, and acceleration. If you don't want to hurt your overall power, you can run a 750 Vacuum Secondary Speed Demon, and install a 4-hole carburetor spacer (if you have the room) between the carburetor, and intake manifold. This will increase the air velocity through the intake tract, increasing your throttle response, and torque.

 

[cokeman277296]

How can a spacer do all that? I've heard they do but how? And also how can the 650 give me more torque and acceleration? I havent bought a carb yet so i still have time to learn alittle more before I decide. After I get that and the cam she'll be ready to put in my truck and fire her up.

 

[Tech @ BG]

Simply put carburetors work based on the velocity of the air travelling through it. A smaller carburetor (ie. smaller venturi) the air will move at a higher velocity, which will increase the torque, and throttle response. A four hole spacer will keep the air moving at a higher rate of speed as it enters the intake tract which has the same result.

 

[GoneNova/406]

don't care for your choice of heads but you have a 400 you can't be all bad.i have a 406 and they love air so go with up to.500" lift or maybe a little more and 280-292 dur. even with a 2.73 gear but your 3.42 will be just right.also dependinding on the weight of your ride a 10 or 11" converter about 2800rpm.a good 750 jetted right is plenty.you'll love it.i'm using a comp cam magnum 280 with 1.6 rockers and can't weight til i get some 1.5 roller rockers so i'll have a bigger choice of cams and go a little bigger.

 

[cokeman277296]

I've been leaning towards the comp Xe268h cam. I wish I had enough money to get a retro fit roller can and lifters. they are very pricey though.. I cant wait to get it in. All I have now is a stock 350 GM crate motor.

 

[cokeman277296]

Guys your not gonna beleive this. I didnt notice it when I 1st got the block but Saturday when we was about to put the crank and pistons in, i was cleaning and wiping the dust off the cylinders, there is a big crack on the wall of the #4 cylinder about 2 centermeters deep. So now I have to take the block back to the machine shop. The machinest said it was a trade in from a guy who wanted another block. I guess he just took his word and didnt check. But he will give me another block and i'll be back on track. Just got to make sure its .040 over or my pistons wont fit. Sucks dont it.

 

[lluciano77]

Guys your not gonna beleive this. I didnt notice it when I 1st got the block but Saturday when we was about to put the crank and pistons in, i was cleaning and wiping the dust off the cylinders, there is a big crack on the wall of the #4 cylinder about 2 centermeters deep. So now I have to take the block back to the machine shop. The machinest said it was a trade in from a guy who wanted another block. I guess he just took his word and didnt check. But he will give me another block and i'll be back on track. Just got to make sure its .040 over or my pistons wont fit. Sucks dont it.

A machinist that didn't take a second to look at a block he was trading for. Yeah right. It sounds like your machinist is a little less than honest.

 

[cokeman277296]

LOL guys dont laugh. I took it down there and it was nothing. He had resleved the cylinder thats all. Im new at this so I paniced, not to mention my friend who was helping me was making it worse. Anyway now that that has been cleared up we have the bottom end in. And I have another question. My heads are 882 heads with 2.02/1.60 valves, screw in studs with guilde plates. Im using 1.5's full roller rockers. Now my question is on the guilde plates. We installed the cam and lifters and put the pushrods in the holes and they were binding alittle agianst the guilde plate to the point they were really tight. I noticed that before we tightened the plates down that they moved alittle so maybe thats it. If that dont work what else can I do? Can I bend them alittle or drill the slot alittle bigger? Im so close to getting it done and this slowed me down. HELP :sweat:

 

[cokeman277296]

ttt

 

[tornado-tech]

Were the pushrod holes in the heads elongated?

 

[cokeman277296]

yeah they were elongated. there just real tight agaist the guilde plates. thought about grinding them alittle.

 

[tornado-tech]

If the pushrods are not rubbing against the elongated pushrod holes and they are a little tight against the guide plates, I would file them down to get a more acceptable clearance.