WS6T3RROR,

Dam good posts, you and I talk alot and I totally agree with what you've said.

The AFR's are the best choice for out of the box power for a BBC, that's why we setup a dealer relationship with them (well that and the new LS1 heads that will be coming out.) A 6000rpm max 489 cube BBC will like the 305's or the 325's, if you were going to go all out and spin that puppy to 7K then the larger AFR's would better. I would spend the money on the AFR's over the other parts any day. The $1935 for those heads is well worth it compared to any other BBC head out there, and here's why. Compared to the Edelbrock Performer RPM, which is 315cc and $1720 per set. For that extra $200 you get 45cfm more @ .600, but the fun doesn't stop there 40cfm more @ .500, 37cfm more @ .400 and 21cfm more @ .300 lift all in a smaller port. That's a whole ton of power and TQ for that money, you will not find a cheaper place to find that kind of power, I would easily say that you'll have 75-100hp more with the AFR's

As for the cam, a BBC race motor likes lift. The only way to get that is with a solid roller, but that's not a budget setup. On the street .600 lift would be a good goal to get to, but that's not going to happen unless you have a solid roller or alot of rocker arm, both aren't cheap. One more deal that the BBC likes is that the valvetrain is some heavy stuff, everything is bigger and has more mass than a SBC. This coupled with the low budget and the relatively low lift (1.7:1 rockers help this out!) means look at a solid flat tappet cam. The Engine Masters rules this year for Big Blocks stated that you have to run a flat tappet, and you can make a ton of power with one on a BBC. The reason a solid is better is because the mass of all of this valvetrain is going to strain the hydrallic lifters too much, and there is alot of power in going to a solid setup. The famous GM LS6 454 was a good example of solid lifter power! When you get into solid flat tappet stuff nobody does that better than Comp does. As far as the duration WS6T3RROR is talking about, that's a pretty dam good range to work in. That will get you close to .600 lift and make a nice amount of TQ. Add on here that the old BBC block like you have is not going to like HR lifters, and you will eat about $400 of your budget up with just those alone! $90 for a set of solid flat lifters just found you more than enough to justify the AFR heads now. You'l also save some money on the cam since a solid flat cam is pretty cheap, The whole valvetrain kit for a solid flat is going to run you about the same price as the HR lifters would if you go with a off the shelf setup. Now that's saving money.

As for that bottom end, you got that dead nuts. Scat 9000 stroker crank, and I beams would be a awesome combo. Since you don't have the stock crank the free cubes and better NEW crank are both a plus since you have to get a crank.

With a few less cubes (470), alot of attention to detail (this is key), a well ported set of AFR's, single plane intake a solid flat tappet cam and a good amount of coatings you could easily see over 800hp @ 6500. You don't have the cash for a motor like that, but you can take alot of those lessons and get one putting out 600hp+

Now throw a Munice behind this (I think my brother in law has one in his garage) and you should be good to go. It will let you run a little more cam too, since it has a closer gear spacing.

I hope this is going in a big Chevelle like a '70. Hell I'd throw it in a '70 GTO or a '71 T/A instead of a old Pontiac boat anchor.

Bret

 

So much information, it takes me a half an hour to just take it in! Do the AFR's that are larger than 325cfm's cost more as well?
It seems that people all have their own opinion on what cam to get, if i was to go with a flat tappet, what lift and duration would work best with my set up?
also, as far as rods go, what length is going to be best?
SStrokerAce,
This engine will be going in a '69 camaro. Love that car!

 

I have heard flat tappets don't idle well? that they don't like lower rpm's... am i wrong?

 

OOPS! You just hit 'Ace's soft spot. He really digs '69 Camaros.

 

I would have no problem running any comp cams lobe as long as the agressiveness of the profile was inline with what I wanted to do and wouldnt comprimise the durability of my valvetrain.

As for going with a bigger port than the 305 I wouldnt do it.
If you are only going to be turning around 6000 rpm or so you wont need it.
The engine is only going to make so much torque per cubic inch and if you set a rev limit to keep your bottom end together for a long time then you will only have the potential for so much power.
After that you need the smallest ports that will flow enough air to make the kind of power you are looking for.
The 305 AFR's already have the potential to make over 700 hp out of the box so stepping up to a larger port volume with more airflow that you cant use will only sog out the bottom end and not really make much more top end power.

You can of course do what you want but overkill on heads and cams is the biggest mistake people make when specing out an engine. Remember that bigger does not always mean better.

 

Is is a RS car with the hidden lights or the standard grille? I'm a big fan of the COPO look. That era of F-bodies from about 67-74 is my favortie. (the new LS1 cars are not bad either)

The 305, 325 and 345 AFR's all cost the same, the CNC ported versions (315,335,357) are all about $600 a set more.

The lift and duration range is the 235-240 @ .050 on the intake and 242-248 @ .050 on the exhaust. That coupled with the AFR 305's will get you a HP peak right at 5800rpm. Throw a big 4150 Holley on that (like a 950 or a ported 850) with a RPM Air Gap and you should be good to go.

The lift is going to be a question of budget & durability, more lift is going to need more $ to work with it, but not like the change from going to Hyd Rollers would require.

You can be anywhere from .540 lift to .620 lift on just the intake side in this duration range if you stick with a stock diameter lifter. The highest lift setups are not street setups, they are way to aggressive and are not good for durabilty. There is about 35hp in that much lift difference though. I would go with something in the middle ground and you would be o.k.

This is another choice in which lobe you pick. You can go with the stock sound of the LS6 or you can have have a little less choppiness with another lobe. It's all based on seat timing or the rated duration numbers. But the duration range and LSA of the cam has more to do with this. It's going to idle a little better than the old H.O. 454's did cause of the extra cubes anyways. With the cams that work right for you, I doubt that you are going to have tha big of a problem with them anyways.

Bret

 

No this is not an RS camaro, it has the standard grill. I like the RS look though, thinking about getting an RS grill. but it is a plain jane camaro, previously had a six cylinder.
So if i went ahead and got the 305 heads, these are not ported?
Are you talking about a flat tappet cam here? Sorry i got lost

 

I dont think you can afford the afr's on a 5k budget.

My son and I recently built a stroked 540 cubic inch big block based on the 10.2 inch truck block this is what we have in it to date and have not bought the heads.

used complete block 300

machine shop work

vat, clean, freeze plugs, cam bearings 150
bore block 100
relieve block cylinder skirts for stroker kit 75
Balance stroker assembly 175
blue print block includes the following 500
a. check for bore shift
b. sonic check
c. check deck trueness
d. rod and drill all oiling and water holes.
e. remove all block flashing
f. port match block to oil pump
g. machine deck surface
h. align bore mains
machine shop total 1000

stroker kit (piston, crank, rods, rings 1660
oil pump 56
gasket set 88
timing chain and gears 103
cam motion hyd roller cam and lifters 500
rpm intake 235
carb 1050 cfm 550
accel distributor 216

total parts 3408

total so far with no heads or headers 4708

I would think that maybe you could do some of the things that the machine shop did and save some money but all the parts are needed on any build so you still wouldn't have enough to buy the AFR heads on this build even though they are great heads. And I don't think the price of a stroker kit is going to change much even if it is smaller.

 

The 305 heads come ready to go, the CNC versions just flow more air.

The cams are flat tappets, yes. The good thing is that a custom grind or a out of the box cam cost the same amount if it's based on the same cam core.

Bret

 

TimeBandit,
Did your block start off as a 502? or a 454? If it is a 454, did you use a 4.50 stroke and a .60 over bore?
You seem like you had the machine shop do alot for your engine, are all those things the norm when it comes to that?

 

we used a 454 tall deck truck block
the exact specs are
4.350 bore by 4.5 stroke
6.535 rods
cubes are 535cid to be exact

And yes it is normal to do all the things that the machine shop did. Although If you wanted to you could do some of the things like port match your oil pump, remove all the flashing from the engine, relieve the cylinder skirts for the rods, drill all the oil holes clean, clean all your oil return holes in the lifter galley, etc and maybe save some money there. But I think once you do it you will realize that the machine shop will do a better job quicker because they do it every day and know all the little tricks.
But if I were going to spend the money to build one I would make sure that the block be sonic tested, checked for core shift, decked, and line bored. The other option is to buy a merlin block It will cost you about 1k more but it is much stronger and is capable of even more cubes.
And of course they will have to balance the stroker assembly.
We also set our compression up to be around 10.3 to 1 expecting to buy a good set of oval port aluminum heads and we are hoping to see 625hp at the flywheel. And have about 6500 to 6800 in the engine.
Hope this helps.

 

I kind of lost interest in this thread. But I still say that if you find a tall-deck block, it's ideal for a street motor. Big cubes rule on the street. Actually, they are darn nice at the track as well.

This really makes me want to get back into big-block Chevys. Now, I just need a car I can fit one in!

Rich Krause

 

How about a truck or a 'Burb? You like the challenge of making a heavier vehicle haul, don't your, Rich?

 

Hey guys I'll give you a good hint as to where to find a good tall deck block.

Find a middle to late 80's up to early 90's chevy dump truck nearly every one we found in a junk yard had a tall deck in it. Even some earlier model 427 tall decks will work. just go to mortec and get the proper casting numbers for the Tall deck 427 and 454 and start looking. It is amazing that a junk yard will charge you out the ying yang for a 502 or a 454 from a performance car but will just about give away a dump truck motor. We found 3 in about 4 weeks of looking and just chose the one that had the least miles on it.

Also we have an excellent machine shop in the baton rouge area and the guy that does the performance work told us to stay away from any block that you can not turn over. Its ok if it doesn't run or if it has a rod knocking etc., but you need to be able to turn it over. He said that these blocks and are prone to over heat and head gaskets will blow putting water in the cylinders, This along with fact that the cylinders wear quickly on these trucks you could get one that has so much rust in the cylinders that the block can't be saved.

And Rich is right the Tall deck is a great way to go It allows you to use longer stroke and rods which has many benefits.

As I said before the merlin block is another way to go and we almost did. but we weighed the cost of our block totally ready at 1300 and the cost of the merlin block at 2500 and just couldn't justify the additional money.

Also do not forget if you find a 427 block it is internally balanced and the 454 block is externally balanced so flywheel and balancer will not interchange.

 

Full-size p/u with a blown big block for strip and occasional street use sounds kinda sweet . Maybe with a Lenco?

Timebandit: thanks for the info!

Rich Krause