N/A 4.1 builds?

[ek02]

I tried to get one of those windage trays but they had stopped making them by that time. I'm not sure it would add 5 horsepower, but Jim Bell had to sell parts. I built some 1 5/8" 3 into 1 headers that I run now from specs I got from Jim Bell. I also built full length 1 1/2" headers and could not see much difference in the seat of my pants. Smokey Yunick said short headers worked best on a V6, but the Busch cars all used full length headers. I run a custom roller cam with the same specs as the KB Mk 2R and I have an original flat tappet KB Mk 2R in my spare engine. The roller runs better, but both have good mid range and top end power. I ran a MK 1 cam and a MK 2 in my 3.8. Either cam would work well in your 4.1. The MK2R idled poorly in the 3.8 but idles pretty well in my 274's with a 2800 stall speed converter. Pocket porting the heads really helps and is easy to do. The KB number one intake has small ports where it meets the heads to help low end power and stop reversion. With ported heads I opened them up to match the heads. I have most of those test sheets from KB from the late 80's. The difference in a built N/A 3.8 and a 4.1 with a stroker crank, GN1 heads, and the roller cam is amazing. In N/A form, the 4.1 is the way to go. Without a turbo you need all the cubes you can get. I use nitrous to make up for no turbo, but after breaking the main webs out of a 4.1, I now use a progressive controller and a lot of spark retard in my MSD ignition box when the nitrous hits. The block is also girdled. It's been fun seeing how much power I can get from a V6 since a V8 would require major surgery to my original owner 43 year old Toyota truck.

 

[jdpolzin]

There are some Sanderson shorty headers on eBay that are designed for a Buick v6 to go into a 40's frame. They say they hug the block well. I thought about buying a set. 1.5" primary. Not sure how well they would match to the ports on a set of ported GN1 heads though.

If you were to recommend an off the shelf roller cam that is available in today's market, which would you use for street duty? Been talking with Earl about pistons to get to about a 10-10.5:1 ratio and we are discussing cams. He's suggesting a smaller cam to keep the power down low. Since this isn't a drag car at all, I'm agreeing. But I don't know if there's room to breath and still be usable at the 3000-4500 range with a larger cam. I'm starting to buy my parts slowly because the money isn't quite there but want to work towards a goal. I know my money will go into the heads and there's no getting around it.

 

[ek02]

The only off the shelf roller cams I know of are for turbo cars. Comp Cams can grind a cast roller to your specs. They have flat tappet cams with specs that could be transferred to a roller. The cost is probably double what a flat tappet is. I would say stay low on duration but get the most lift you can. I may have the specs for some of the old KB cams around. I'll take a look. 1 1/2" headers work with iron heads because the port size is about the same. GN1's have ports that match up to 1 5/8" headers. For the street the 1 1/2" headers would probably work fine if you are using iron heads.

 

[ek02]

I could not find the cam card for a KB Mk1 but it had .456 lift and a 114 LSA. I think the duration @.050 was around 218. Very similar to a Comp 69-246-4. The Mk 2X had .478 int and 494 ex lift. The duration @.050 was 214 int and 228 exh.The LSA was 112. All their cams were ground with 4 degrees of advance. The MK 2 was degreed on a 107 intake centerline. This cam idled with 15" of vacuum in a 3.8. You really needed a 2500 stall converter with it. Comp has 4 flat tappet cams listed for N/A v6's that could be ground on a cast blank. The 4.1 will idle smoother than a 3.8 with the same cam due to it's larger displacement. My cams are MK2R's, not the 3R which is a 106 LSA and idles really rough.

 

[jdpolzin]

Any idea where I'd be able to a get larger set of headers? Were there every really any available?

 

[ek02]

The only 1 5/8" headers were the 3 into 1 short headers with a long slip fit collector were made by Kenne Bell and they would be very hard to find now. Sanderson is the only manufacturer that may have something that will work. They made some flanges for me about 8 years ago.

 

[jdpolzin]

I'll get ahold of them and see if they can make a larger set.

 

[earlbrown]

Pistons and static compression are no problem, but have you decided on crank and rods yet?

If you're going to run chebby rods I need to put a .927" pin in them instead of a Buick pin bore.

 

[jdpolzin]

So far I've decided to definitely use my stock stroke NA crank and stock rods. Also this 206/206 roller cam, and Weiand Smokey Unik intake. I also have an Edlebrock 1406 600cfm carb. This has an electric choke so I'll need to figure out how to make that work. Still need to find some budget aluminum ported heads. I do have a set of newly done 6293's with big valves but not ported. I could port them myself to save some cash but I've never done a set of heads. Might not do them any good. I'd like to get as much out of the heads as possible so ported aluminum heads might be my best bet.

 

[earlbrown]

If you polish the combustion chambers and bowl port the heads you'll be well over 80% of the way there. Smooth out the pushrod pinch, CC the heads and do some math.

Here's a set of heads I did years ago just for the funs of it.
http://www.turbobuicks.com/forums/buick-v6-turbo-tech/79654-how-put-set-heads-together.html

Look real close at the pictures I show two combustion chambers and you can see the bowl openings. In real life it was like ''goddamn, why did Buick do that??" In pictures it looks like I shaved just a little bit.

Keep in mind aluminum sucks heat out of the combustion even and puts it in the water jacket instead of turning the crank.

....and, oh yeah, is pretty damn pricey too!

 

[ek02]

If your iron heads already have bigger intake valves, the bowls may have already been enlarged. If not, it's easy to open the bowls with a hand grinder. For low and mid range power, your heads should work fine, although the aluminum heads will for sure make more power. I have identical N/A 4.1 stroker motors with aluminum heads and roller cam on one, and ported irons and flat tappet cam (same specs) on the other. The aluminum head engine for sure has more power but both are about the same at lower RPM's.

 

[ek02]

It would probably be overkill, but the money saved on aluminum heads could be spent on a stroker crank. You are having custom pistons made anyway, so it would be the same price. Stock rods do not have any rod to cam clearance problems like H beams as far as I know, but would still need to be checked. I remember checking it a long time ago with a stock rod and there was plenty of room. More torque at low RPM with the stroker.

 

[jdpolzin]

Can the stock flexplate and balancer be used on a steel crank? Stock rods with a stroker crank since the pistons are being made anyhow?

 

[earlbrown]

If it's an internal balance crank the balancer and flexplate will have to be neutral balanced. They're made for an external balance crank.

 

[jdpolzin]

Do you guys know if a Chevy balancer that doesn't require a relucter ring can be used on our motors?

 

[earlbrown]

I doubt it. Chevy's most likely have a different sized snout. Not to mention they are press fit when our shit isn't.

 

[INEEDAGN]

Polzin I forgot to mention, when I find the external hard drive at my house I will post pics of one of Smokey Yunick's v6 builds. I stumbled across it in the Don Garlits museum in Ocala, Florida in 2013 and took fairly detailed pics of it. It was a complete setup. I just kept staring at it thinking "what I wouldn't give to see the inside of that fucker".

 

[ek02]

I forgot about the flywheel and damper for an internally balanced crank adding to the cost. The crank can be balanced for external balance, but its more expensive. I used a TA balancer and a used JW heavy flex plate on one engine, and a BHJ balancer and a CAT lightweight flex plate on the other, both for internal balance. Both engines were balanced to 36.6% by two different shops. Both have a vibration at exactly 3600 RPM, smooth everywhere else in the RPM range. Probably due to hard mounts and being in a tin can of a mini truck.

 

[jdpolzin]

Yeah I think the balancer and flywheel will put me out of the price range to be able to run a stroker crank. I'd love to do it but just dont have the funds. I'm starting to think using my 6293 big valve heads may be the best route as well. Just need to find someone that knows how to port these heads correctly.

 

[jdpolzin]

Polzin I forgot to mention, when I find the external hard drive at my house I will post pics of one of Smokey Yunick's v6 builds. I stumbled across it in the Don Garlits museum in Ocala, Florida in 2013 and took fairly detailed pics of it. It was a complete setup. I just kept staring at it thinking "what I wouldn't give to see the inside of that fucker".

Wish I had that thing!