[leftoverchrisac]

1. I recently picked up a 454 4 bolt main high performance block with crank rods, and pistons from a friend. He also threw in a set of forged 427 banks turbo pistons. I plan on building a turbo motor eventually but it will be a n2o motor until I get more funds for the project. Some people have told me that in order to install a 396 crank in the block to make it a 427 I will need to have it align bored and others have said I wouldn't need to. What is the truth about that?

2. Also, I'm looking for something fairly streetable but I still want to make a good amount of power. I will have 8:1 compression and am trying to figure out a good cam. I have 4.88 gears and will be running a th400. What is a good n2o/turbo cam you guys can recomend? I'll probably be going with a roller cam but would use a solid. I would prefer have a cam that wont put my powerband too high. I don't want to have to replace valve train components every weekend.

3. I know I need more main and rod bearing clearance but how much clearance should I have? Can I buy oversized bearings or will I have to have the block machined?

4. One more thing, what should I go with for a tq converter that would go well with the n2o or turbo?

O yea, is there any machine work I will need to have done to get a 396 crank in a 454? Cuttin things for clearance maybe?

[rifraf]

First off you need to decide if you are or arent going to turbo the thing for sure,a turbo motor without one is a dog,then,if you are,you need to know how much boost your going to have,you need to determon a goal before you go choosing parts because they all need to match,as for your block and crank,you should at least check your line bore no mater what you are building,but as far as if you have to,no,if its good a 396 crank fits right in,you just buy 427 pistons and use 454 rods,good ones,again,you need to know your boost before you choose your pistons,also,know what heads your going to use because this will change your compresion also. As for a cam and stall? How big is your budget and where do you want your rpm range to be,where do you want it to come on exactly? Then you choose a stall,usualy bigger than you need to help activate the turbo,turbo lag sucks,thats why I like blowers. As for bearing clearance,depending on the boost and rpms,about .002 on the mains and .003 on #5 with a loose .002 on the rods,but again,it all depends.

[5foot2]

Assuming this is going to be a street machine, that is a lot of gear for a three speed trans witha 1-1 high gear. With 4:88 gearing and even a mild big block (like a turbo motor before the turbo spools up) your going to get a nice jump off the line, then the turbo will spool up and traction is an issue.

If I were building a turbo big block for the street, I'd go with 3:73 or 3:55 gearing and let the motors torque do the heavy lifting on the bottom end before the turbo comes into play.

Another thing to think about with 4:88's on the street is highway driving. If this car is only going to run down to the local hot spot and stomp on the ricers low gears are likely fine, but if you need to hit the highway for anything your going to hate driving that car. Think 3400-3800 rpm at 65mph depending on tire size. I have 4:11 gears in my GMC dually ton truck, with pretty tall tires and I'm 2700rpm or so at 60-65. It drives me crazy. I've long wanted to replace the gears with something higher.

[rifraf]

No doubt,my old nova had a fairly stock 427 with a 4:11 posi,and it was a real bear to hook up. I cant even imagine 4;88s. 120 and I was wound tight,you would be pushin it to see 100mph.

Mine turned about 3100/3200 at about 60 w 4;11s and 15 tires.

[leftoverchrisac]

I'm not worried about the gears. The only reason I mentioned them was to give you guys a good idea of my setup.Also, I already have pistons. Banks flat tops.

Another thing, while it wont have the turbos on it, I will have the bottle on it, so it will be far from a dog. I'm just looking for some recomendations on a cam. I said I didn't want my rpm range to go over 7000.

[Siggy_Freud]

Well for the turbo your going to be wanting to build a very low compression setup so you can run decent boost in your engine. Your not going to want to be hitting the N02 button every time you want to make up for the turbo's not being present. How long after the engine buildup are you planning on turboing it? Depending on the heads and cam and what not, I dont know if flattops are going to be your ideal pistons to run a turbo.

Im sure someone with a bit more turbo experience (TurboS10 probably) will comment.

[leftoverchrisac]

Can anyone recomend a cam for me?

[rifraf]

Well,you still will need to decide where to have it come on,a roller cam will give you a wider power range and allow you the use of a lot more needed spring presure,the idea is that you need to focus more flow out the exhaust than the intake,this can be done by the cam grind,the exhaust valve and port,and rocker ratio. Again,I dont know your budget,and some of this stuff can get real spendy matching it up, but a cam I put in a freinds 454 with a 671 blower that was pretty hot was a crane powermax,we ran the 1.7 on the exh,but 1.6 on the intake side. It was 244/256 dur- int .632-.632 exh. with the lessend intake rocker ratio it came to around .595 lift on the intake. We ran it 4 deg advance,7 1/2 cr,and 14 psi boost. It pulled very strong to 7000,this was using a hughes 8 inch converter and 4;11s in a 3600 lb car,it worked very well.

[Robinson Robin]

A high rpm big block with turbo and nitrous....I hope you intend to use the very best bottem end components money can buy and do some very careful tuning if you intend for it to live any time at all