OBS 5.7 Build Questions

[Mudd Duk]

Got some questions regarding the build I'm currently in the process of doing on my 1990 5.7. The block has been bored over 0.060 with an Eagle crank thats been turned and polished, a Bullet cam (205 and 215), and it's got Keith Black flat top pistons. The heads currently are stock, but have Comp Cams Magnum Roller Rockers, 1.6 ratio. It's got an Edelbrock performer intake for carbureted engines, the truck was and still is FI, so that I could install the Holley Pro Commander 950 4 barrell throttle body with 65 lb/hr injectors. The motor is topped off with a K&N 14" filter. The 700r4 trans was rebuilt with better steels, bands, etc. It does have a corvette servo and a B&M external cooler. The converter is new, but I'm pretty sure it's close to oe stall, 1650 or so. It's a GM18A. Since I'm running the Holley Pro Commander, I had to put a B&M torque coverter lockup controller in it so the trans will still shift into 3 and 4. The truck has been regeared to 4.56 and has a spool in the rear. My questions are:

1. I'm going to run a larger cam. I will buy new lifters and pushrods to match. Can I go with a roller cam if I get roller lifters, or does converting my engine to roller consist of alot of more machine work? Truthfully, I'm not sure if the cam in there currently is flat tappet or roller. Basically, can I buy a roller cam and lifters, and they just slide in, or do I need to stick with the flat tappet (if thats what the truck was originally)?

2. I will put better heads on the block. I believe that the aluminum GM performance vortecs are the best for this build, having 62cc chambers and 210 intake runners. Am i wrong? Also, can I run my 1.6 roller rockers on this head?

3. The cam I was looking at was a Comp Cam Extreme Fuel Injection cam but heard that the cam isn't big enough to get the most from those heads. Suggestions on the right cam? I would like to go with that same brand and series, what one provides enough lift to get the most from those heads, but still mantain streetability and the use of my accessories.

Keep in mind that, since the trans was just built, I won't be using a different converter for this build. I believe that some cams require a larger stall in order to work right. I also want to use the 1.6 rockers I already have in this build too. I know the Comp Cams extreme FI cams allow the use of these rockers.

Thanks for any and all help.

 

[supjim12]

1. I'm going to run a larger cam. I will buy new lifters and pushrods to match. Can I go with a roller cam if I get roller lifters, or does converting my engine to roller consist of alot of more machine work? Truthfully, I'm not sure if the cam in there currently is flat tappet or roller. Basically, can I buy a roller cam and lifters, and they just slide in, or do I need to stick with the flat tappet (if thats what the truck was originally)?

This one I have some experiance with just buy a complete roller cam setup will include everything cam, push rods lifters and rockers. You maybe able to squeek a 1.7 in. rocker but 1.6 should work.

Are you also doing head works to the new heads and also work to the intake manifold? Port and polishing things like that larger valve so forth. Sounds like you are working out the plans before you are ass deep in **** and get all messed up.

 

[Mudd Duk]

First off, thank you for an educated response and answering some questions. It's been a real headache getting REAL answers. So you're saying if I buy the roller setup, it will work with this motor? I just don't want to do anymore machining to the block. As for the heads, I am trying to steer away from having them worked. Thats why I'm trying to get the best head for the build. Yeah, I am trying to get all my answers before I tear into it. I've got access to a shop with all the right tools, and mechanics, just don't want to get there and realize something like "Oh I didn't know a roller cam wouldn't work", or "Oh I tought this was the best cam and head setup".

 

[supjim12]

First off, thank you for an educated response and answering some questions. It's been a real headache getting REAL answers. So you're saying if I buy the roller setup, it will work with this motor? I just don't want to do anymore machining to the block. As for the heads, I am trying to steer away from having them worked. Thats why I'm trying to get the best head for the build. Yeah, I am trying to get all my answers before I tear into it. I've got access to a shop with all the right tools, and mechanics, just don't want to get there and realize something like "Oh I didn't know a roller cam wouldn't work", or "Oh I tought this was the best cam and head setup".

A complete roller setup will drop in no machining. Make sure the cam bearing have been replaced before hand though. Like I stated it will should include everything just depends on who you go through. A decent roller cam and 1.6 rockers will have a different length pushrod hence the kits avalible. The nice thing about these old chevy engines is the fact they are the same (other then bore/stroke) in deck hieght so most companies will offer the completet setup for what you are looking for or at the very least get the parts organized and prepared for what you needs are. The best thing I can recommend (if you have not gotten a roller cam yet) is to talk to your performance supplier, they should be able to help you out with your needs and get a cam set up (lobe /lift/ duration) that you are looking for. The reason why I asked about the machine work is because some people neglect this area and feel it is not important. Doing a port and polish (since the heads intake and everything else will be off should net you some more torque/power with out putting a bunch of money into larger valves.
Just keep asking questions and people will help you out the parts are out there and you can go from mild to wild but the fact you have a plan is great most people just throw things together and get pissed and give up.
Before you have any work done at ANY shop get referances or over look the work make sure they (or the guy working on your car) knows what they are doing. Some shops will hire people who are book smart but never tore apart of engine before.