guys,

I need your opinion. I want more power. 650-700+ hp/tq.

Ive got a 468 with GM 990 heads and a solid cam thats 240 @ 050 with 570 lift. CR is about 9.8:1.

Ive got some tuning to do, but even if i perfected this combo, i aint getting that kind of power. So i need to throw parts at it. I want it streetable. I dont need vacuum, just pump gas and an idle of 1000 or less.

If i added AFR 305/315 heads and a decent solid roller cam with 10:1ish CR, will that get me there? im thinking no.

If i were to step up to a 540 block, would the 305cc's be too small? What size would nicely with the 540?


thanks

jeff

IMO with your idle and pump gas requirements you will want a power adder of some sort. Either N2O or a blower.

I would build it so it makes 550 on the motor and add another 150-200 HP of N2O

650 NA may be doable with a 540 combo, but it won't be cheap to do it right and keep it streetable.

well, Car Craft did the Vortech supercharger 454 with AFR 305 CNC heads and made 900 hp.


Ive been eyeing a procharger F1R/F2 for a year now.

But by the time i get that installed with the blow through carb, bypass valve, new fuel system. im looking at what 6K+? and then i gotta buy the heads and cam...and probably a crank.

I was just wondering if it might be cheaper/better to build a 540.

if i just added the AFR 305s and a solid roller, what kind of power do you think id be at?

thanks Eric

$6k is probably a little "light" to do it right with your existing long block IMO. Never installed a centrifugal blower myself so who knows . . . can tell you though I am ALWAYS over budget.

If you go the route with heads and roller cam with your current short block assuming everything is optimized . . . probably somewhere around 600 HP or a little more depending opn cam size and compression.

12K?? not including the heads,crank,pistons and cam setup? Ive priced the F1R and F2 setup with a couple different speed shops. and the parts come to around 6 grand... what am i missing?

yeah, id try to do most of the assembly myself. i already got #$%@# once.

thanks

600 horse is not a huge order with a 468 imo. Look at it this way, a good performance motor can make 1.25 horse per cube, with a decent bottom end (no crazy high end parts) and good heads/induction and cam. So, at 1.25 per cube, you are looking at 585 horse, and then I agree with Eric, put a 150-200 horse kit on it and your over 700 horse. I think with the items you list, and push the compression as close as possible on pump gas (running N/A), your real damn close.
Or, go centrifugal blower and make as much HP as your block will hold. That will cost you though, you'll need a stout bottom end.
As for cost, I don't know, I'm more familiar with street strip smallblocks, the bigblocks I have experience with are race only pieces for the most part. But with a 550 horse motor, and not getting crazy with nitrous (that never happens :D ) you could get away with a budget aftermarket crank and rods with a good forged piston, then the heads you want and a cam to match, I'd go solid roller too. Definately not break the bank expensive.
Just curious, but have you had a car with 600-700 horse? Thats a lot of power for the street, I personally would go with a motor in the 550-600 horse range and a 200 horse shot, for when you just gotta have a little more. Then you can enjoy driving it a bit.

ive been in a 600 rwhp car and yeah, i like it :)

so what size AFR heads would be good for a hot 468/496? AFR 305s?

Would those heads be too small on a 650-700 hp 540?

thanks

600 is a walk for a 540. That's maybe with an RV cam :D Most of the hydraulic roller cammed 540/555 combos are in the 700 - 750 hp range and 800 is doable with a street roller setup. I'd probably go with Dart 345 Pro 1's for the street, 355 CNC for strip. If you stick with your current size or go 496, I'd probably look hard at Canfields, maybe the smaller Pro 1. Just my .02

650hp with aftermarket heads is pretty easy on pump gas with a 468-496.
My 502 makes 625hp, and is streetable. You could do it with heads and a cam in the 250 range, 2" headers, HP950-1000, and a good single plane. Now why would you want a 9sec. streetcar?:thumbsup:

DONT BE AFRAID OF COMPRESSION. you can easily go with 11 to 1 with an aluminum head motor and the right cam. Of course you have to be carefull and know what your doing but its very doable.
I'm building a '69 as we speak with a 555 and small 305 AFR's, a small .680 roller,and 11 to 1 compression "with cp pistons" and it dynoed at 785 hp and 750 ftlb's TQ the only thing on this motor i question is the dominator carb.other than that its very streetable and showed no signs of detonation on the dyno with 93 octane.

As far as your 468.....My bracket car has a 700 hp 468 and i think it would very streetable. Its got 11.5 comp., merlin 2 aluminum heads, victor jr, 950hp carb, and a small .590 lift solid cam.nothing special at all, and its gone 10.000 at 135 mph weghing 3450 lbs.

Go with a 540/555. Its hard not to make 700 HP

I am not convinced that you need more than 10:1 CR. But that is a debate here that will go on forever.
I run 9.4:1 and all we get here is 92.
My engine is a 498 and it made right at 700hp @ 6250 and that is 1.4 HP/CID. More than a few here argued with those numbers. All dynos can give diff results.
In a 3500 lb car it has been in the 9.90's @ almost 134 in 80 degree heat. I believe these numbers agree reasonably well with the measured HP
I use the AFR 305's with the CNC chambers.
The cam is all but huge for a 500" engine. I drive it all the time, and always to the track.
AFR told me that 650 was possible at 468" with these heads. That is 1.39 hp/cid.
I think about a procharger as well, but I have too much CR to run much boost on pump gas, and I think if I added 2-300 more HP, 2 things would happen. Everything aft of the crank flange would break, and I'd have to buy lots of sets of underwear.

I believe the AFR heads are excellent, and under rated in the press. The 315's would be the way to go. I wish I would have gone with them, I'd be in the 9.70 range. I still have tuning to try.

BTW....when you get to the 650 to 700 range, better have the converter, suspension and tires working optimum, otherwise it tire spin city! I was there earlier this year.

Have fun!

Ron

i just got my mickey thompson 275 et streets and my converter is my left foot. ive got the cal tracs and split monos too. i probably wont hit the nines with my driving and the TKO, but it will be a fun street car :)

What is your cam specs and carb?

thanks guys!

Cam is 260/266 .677/.687 (gross) and 110 lobe sep. It would be a little large in a 468. But you do have that man trans.

I run a 1050 Dominator.

If I had a 540, I think the 315, 325 or the 335 AFR's would all be good choices.

Ron

Just to be clear, I have no doubt that 650-700 HP could be had with an NA 468" motor. The question is streetability in my mind and "streetability" in this case was defined early in this thread as "pump gas and an idle of 1000 or less"

The big variable here is what short block he has now and if it can be built with 11:1 compression and meet the criteria above. Maybe it can, but I am not as knowledgeable about BBCs as I am SBCs (and never claimed I was ;) )

That said, getting the most out of this 468 and keeping it pump gas friendly and idling decent would involve close to 11:1 compression, a cam in the 250* @ .050" range and good heads with good port velocity. In other words, not the big heads with the biggest flow numbers, just good flowing heads (as in 325 cfm) with the right port cross-section.

From what I have read the Canfield heads flow real good out of the box but the port cross-section is pretty big. There is a thread at www.chevelles.com that goes into great detail on these heads and what was done to speed up the port and increase flow.

Just looking at the AFR catalog the 305 "as cast" heads look like the right choice for this type build -- they advertise 358/272 cfm at .600" lift which should be enough to support just over 700 HP with the right cam.

The idle RPM with an 10.5-11:1 motor and 250* roller cam should be similar to my small block or a little better at about 850-900 in gear 1100 in park.

Not sure what kind of power numbers that 468 combo would put down . . . I think over 600 should be pretty easy.

PS. and Ron's combo seems to be killer --- if you can handle the cam you may want to try duplicating that. :D

Im with Ron, a lot of people dont realize how easy it is to build power with Large inch big blocks. If you dont have the money stick some 315's on your engine and a voodoo SR feed it with a dominator and youll be in the 650 range. If you built a 540 at 10 to 1 compression up the heads to AFR 335 and jump to the 750 range no sweat. It might be better for you to sacrifice the low end and buy the 335 heads now in anticipation of going to a larger engine later. depends on your funds. 700hp on a SR cammed big block is easy.

Shawn

How much power does your engine have now (with the 990 heads), and how does you car run with it? I'm curious because I have a set of those heads too and plan on trying them on a 454.

Its tough to get 11 to 1 without going the custom piston route. I ran into that problem with the 555. you either have to low or to high. Cp will make any piston you want ,any dome size/compression ratio.

Ron489.....you probably have out of the box srp's or je's right ?? with the cam your running you could easily run 10.5-11.0. I think 9.5 is a little low. But hey....it runs awesome so who am i to say !!!!

We put Afr 305's on a 555 !!!!! .We were looking for big tq numbers for the street.I've always found that when it comes to cams and heads......smaller is usually better.

Why don't you go to your favorite GM Dealer and get a 572/620. If you dial it in you can get what you are after plus a 2yr/24000 mile warranty to boot.

by the way, do you think a 7416 crank will handle this power (650-700)?

Dutch,

The motor is ok now. it pulls pretty hard. i just got my new 275 mickey drag radials. ive never been able to hook before, but hopefully will now. ... im probably close to 500hp.

thanks all

Its tough to get 11 to 1 without going the custom piston route. I ran into that problem with the 555. you either have to low or to high. Cp will make any piston you want ,any dome size/compression ratio.

Ron489.....you probably have out of the box srp's or je's right ?? with the cam your running you could easily run 10.5-11.0. I think 9.5 is a little low. But hey....it runs awesome so who am i to say !!!!

We put Afr 305's on a 555 !!!!! .We were looking for big tq numbers for the street.I've always found that when it comes to cams and heads......smaller is usually better.

I am running out of the box SRP's. And you are correct, you either get near 10:1 or 13:1, nothing that we could find in between w/o going custom.

I was aiming for 10:1, but the pistons were at 0 deck to about +.005 out (due to tolerance stack up) so we had to go to the .051" thick head gaskets. also the AFR's had 121cc chambers and the piston specs were listed at 118cc for around 10:1.
We could have milled the heads etc, but just didn't think that a .4:1 change in CR would have made much difference.

I don't mean to brag about the combo, just try to state what we did and how well it came out. I'm still surprised at it all.

Ron

I too am running out of the box SRP s, I noticed the same thing either 10to1 or 13. A few combos showed a 21cc instead of 18. I didnt want to leave any compression on the table with my cam after the combustion chambers were cnc machines i had my AFR heads milled back down to 116cc with my pistons .005 down comes out at 10.5 to 1.

Shawn

what about the 7416 crank. can i use that for 700 hp? or do i need something else?

thanks guys

Reg. 87 oct. gas is $2.97 avrg. Cam 2 race gas is $4 and some change. Might as well do what I did 13:1 and loving it. It's not my daily driver so it don't matter. I had an 11:1 motor before and it's ok but why stop there? To high for 93 oct with steel heads racing and if ya gotta buy race gas get the power with it! :) http://www.nescaracing.com/polishsneakers.html

Reg. 87 oct. gas is $2.97 avrg. Cam 2 race gas is $4 and some change. Might as well do what I did 13:1 and loving it. It's not my daily driver so it don't matter. I had an 11:1 motor before and it's ok but why stop there? To high for 93 oct with steel heads racing and if ya gotta buy race gas get the power with it! :) http://www.nescaracing.com/polishsneakers.html

A couple years ago that wouldnt make any sense......But now,it makes perfect sense !!!!!!!

bob

Tremec + 700 Hp = Good luck
I own a Tremec and I love it ,but I doubt it would live behind a 700 Hp BB
Maybe it would last with street tires ( Hot Chick big Boobs who is a bittcch ) Whats the point

Dominate- Where are you located in AR? We might not be far apart.

I figure this combination will hit at least 700hp N/A easy, but not exactly cheap tho...

A standard deck height Merlin or Dart block bored out to 4.625" and a 4.375" stroked crank to make a 10 to 1 CR, 588" with a cheaper set of 350 to 360 cc rect. heads and say a 295/255/300/260, 112/108, .625" net lift solid lifter cam and a Strip Dom and a 1050 cfm Holley three barrel or something in this cfm flow range.. (Or some such solid cam from Harold??)...

Almost forgot headers that are big enough for it to breath but not so big, they start subtracking midrange grunt.

pdq67

PS., and I would use a 6.450" long custom rod and matching piston to give me my about 10 to 1 CR. with the piston at the top of the stock deck height so I have to use my headgaskets to set my quench distance...

He, He!! The big sucker would look about like a 396!! talk about "STEALTH"!!!.. He, He!!

My combo goes like this. 427 + .060 = 440. 11.25-1 TRW. OVAL PORT Edelbrock RPM performer Marine heads, flowed 318 on the good port 288 on the bad and 255 on the exhaust @ .600 Valve lift. This was after some head work. Cam is a Hydraulic roller .648/.648 .245/.255 @ .050 on a 112 LC. A holley Strip dominator intake, and 850 DBL pump with 38 degrees timing. The motor made 550HP @ 6350 and 513 TQ at 4750 on the dyno. In the car is another story, it ran 11.72 @ 115 MPH on the motor, on the bottle it ran way better. 10.37 @ 127 MPH with a 1.45 60'.with a 150 shot. And a 9.92 @ 130 MPH 1.39 60' with a 250 shot. So the car is designed to run on the bottle, and it works so/so on the motor. cant get the best of both worlds i guess.

The new motor I am building is a 468 BBC with 12.3-1 SRP pistons, AFR 305 as cast with CNC chamber heads, and a solid roller. .691/.684 with .260/.270 @ .050 on a 112 LC a Adrt rec port intake and a Barry Grant 825 Mighty demon carb.I am running a 2" hooker race header as well. AFR tells me they have seem combo's like this make 650 HP . My engine builder tells me close to 680HP. I guess the dyno will tell all again. I plan on hitting this with a 250-275 shot again too. I am looking for a mid 9 second pass with this new combo, not to shabby for a street car.