bbc aluminum heads dilema

[brunz21]

so Im getting ready to go to the track for the first time this year to see what the 'bu will do, but one issue thats been bothering me is the fact that my heads are way too large for my motor. i still want to see how fast it goes with the current combo, but it bugs me that the mistake is my fault. here's my dilema; i have a .100 over 454 4 bolt ls-7 hi-perf block, steel gm crank from same block. eagle h-beams, diamond 10.5:1's, bullet solid roller .722/.697, bullet lifters, piston oil squirters, and some other little trick stuff. its topped off with the merlin III 350cc alum heads, matching merlin intake and a 1050 ebay special. i have a huges 4200 stall (thanks pete) and th400 R.M. with brake. 9" ladder bar and 4.56 gears, soon to be 4.11's.

i got a smoking deal on the top end package, and wasnt too savy on the whole head size vs. cubes deal. needless to say i was wondering what i should do. i wanted to run high to mid 10's on that combo, and still put in some street time. is there any remedy other than buying smaller heads? ive got a ton of money in the short block and the heads, and id hate to have to spend even more. ideally i would have gotten one of those shaffirof 572 incher short blocks with a hyd roller to be more streetable and still run 10's.

what would you big block guys do in this situation? im hoping to get some chassis dyno time this spring so the builder can dial it in for me, so we'll see what the numbers are. i also have the cam duration numbers which i can post later when i get home. all in all, theres over 11 g's in the short block and i cant justify just dumping it and starting over. this was an expensive lesson, but now i know what i would do differently. what do you guys think i can get for that short block should i decide to sell it? am i making too big a deal out of this?

 

[prairiehotrodder]

$11000 in the short block !!! You must mean long block?? I built my 489 With AFR 325 heads for around $9-10 including a pro-systems 1000 carb and all new parts, nothing used. How does it go? Does it really feel like the heads are to big? No power untill you really get the rev's up?
brian

 

[brunz21]

yep 11 g's in that thing man. lesson learned on that one. 3 sleeves, decked the block, oil squirters, custom pistons, custom cam, blah blah blah. oh and it took 3 years and me kicking a display for the machine shop to get it done. around here i cant get my foot into it for too long without hitting traffic or a red light or getting arrested, but it goes like h ell on the street. its hard to say cause its too much motor on the street here as it is. once i get past about 4,000 rpm (converter) it takes off, and who's ever in the passenger seat starts gripping the cage and screaming to slow down. but again, no numbers to prove anything yet. i had most of this bbc stuff already and figured it would be cheaper to use what i had. WRONG! im still excited to see what it does, but im just irritated that i planning could have been more optimal. just kicking around some ideas i guess. ive been eying those shaffirof short blocks lately.

 

[Ed Cannon]

Just my .02 there's no easy remedy. It will probably be a dog down low. If I were you I would take the top end off sell the heads and put the money towards a proper set. And chalk it to lesson learned. I think in the end you will be glad you did.

 

[boostinmalibu]

if it was me, if leave it and hit it with a 100 shot at the track if its a dog down low, whats the duration on the cam?

 

[brunz21]

so my cam duration at .050 is 251/262 and at .020 286/294 i did have the rings set for nitrous and i was gonna hit it with 100-150 if i didnt get to where i wanted to be.

 

[bracketchev1221]

Sell the heads. 100-150 hp and they are still too big. How much power do you think it will make? I can tell you I have a 540 with 355 CNC Dart Pro 1's on it. Shift at 7500, cross at almost 7700. Cam, is 275/[email protected], 307/321 @.020. .788/.762 lift. 4.56 gears, 5500 converter and trans brake. Leave at 4600. Gone 9.0's at 148 and the heads are STILL too big for my motor at 3200 lbs N/A. I should have a ported set of 335's at best.

 

[red barn]

I leave the engine building to my friend, because that is what he does for a living...however I try to pay attention to what he says and learn what I can. Doing the assembly work on my first "self built" motor with him looking over my shoulder in the next couple of weeks.

Based on the 3 big blocks he has built for me, I would say your heads are too big and that selling them and getting something different may be a good option.
As a reference, my pump gas 468 made just a tick above 600 HP and runs 10.80's in my footbrake car (1978 wagon) with me leaving at 1800 rpm (that's were I can cut consistent lights) and shifting at 6300

9.8:1 468
GM forged crank (I think those are 5140 and not the good 4340)
Crower sportsman rods
SRP pistons
Brodix BB-2Plus heads (312cc)
Crower stainless rockers
Brodix HV-2000 intake
680 lift solid roller (i don't remember the rest of the specs off of the top of my head)
950 Holley

with your shortblock, which has a little more compression to use the larger cam you have and the trans brake, I would think the BB-2 plus heads would put you at the 625 - 650 HP range and run mid to high tens without much fuss

 

[brunz21]

thanks for the good info guys. after some stewing about it, i think i may try to sell the short block and get one of those shaffirof street strip 582's with my heads with a hearty hydraulic roller. i like the brute sound of the solid roller, and all the trick sh t i have on this block, but honestly i want to drive to the track, make a ten second pass, and drive it home. i want a somewhat reliable driver more than a race car. i may run it this season to see what happens, but id rather not risk hurting the motor and just sell it. anyone interested in a short block??? what do you think i can get out of it if i try to sell it?

 

[prairiehotrodder]

if i had a 582 I would want to run 9's not 10's. I think you have to much money. Would you be interested in sponsoring me? j/k

At least run what you have and see how it goes at the track.
brian