Harold,

I am in the process of rebuilding my 427 (.030 over). The motor is an L-88 short tat I will be dropping the compression ratio in down to about 10-10.5:1. The motor will be running 990 heads and it's in a full steel '72 Chevelle with 4.30 rear. The car will be used for cruising as well as trips to the track a few times a month. Your suggestions?

Bump

Let me know if you have a 4-speed or an automatic. I am assuming a 4-speed, but I need to know. With the compression and rear gear, I have a number of mechanicals, both in the catalog/website, and custom cams in between.


UDHarold

Automatic, TH-400.

L-71,

Depending on your converter, and what you want the cam to be, I have the following:
402A1LUN--272 at .020, 238 at .050, .550 valve lift, 110 LSA. Used to replace LS-6 cam, improved everywhere....
402A2LUN--272/282 at .020, 238/248 at .050, .550/.570 valve lift, 112 LSA. Wider power band, more top-end. Both these cams are once-a-year for valve adjustment.
402A3LUN--276/284 at .020, 243/251 at .050, .586/.600 valve lift, 110 LSA. Most popular street-n-strip BBC cam. Should make about 510 BHP in your engine.
402A4LUN--282/292 at .020, 248/255 at .050, .570/.586 valve lift, 112 LSA. Another once-a-year for valve adjustment, lopey idle, needs 3500 SS converter in 427.
402A5LUN--285/295 at .020, 252/261 at .050, .595/.595 valve lift, 110 LSA. Streetable racing cam, needs 3500 SS converter and 4.10s in 427. Racey idle, and meanest-sounding.
I would not garauntee that any of these cams would work power brakes in a 427, so you will need a vacuum pump set-up.
They all need a good high-volume mech pump and 1/2" #8 fuel line, tank to carb.

UDHarold

While its hard to compare, the A3, in my case with 10.51:1 measured and 'decent' quench ( not great) does occasionaly 'cough' on 93. I do have the cam in +6 as per Harold's recomendation. He also did warm me about too much CR, as 10.3:1 was my inital goal. Whoops. A little decking here, milling here, and now its 10.5:1. (the 248 @.050 cam would have been a bit better for 10.5:1, but would take the rpm band above 7000 imho)

Could be my quench sucks? Mill doesnt. Goes at 'round 118 mph at the traps. I'd say Harold's 510 HP guess is darn close.


A3 is a great cam as far as powerband goes IMHO. You'll be shifting as high as 6800+, but I wouldn't try and squeeze 10.5:1 with it again, myself. 10.25 TOPS! A little wiggle room for bad gas. There's none of that when the DCR is at max ( 8.5-8.6:1), as it would be with that cam at 10.51 CR and advanced 5-7 degrees.

I would consider, if min ET is not a top priority, having that cam on done a 112 lsa instead of the "stock" 110. You should get by with brakes and it will sound a bit more "LS6-like" at idle. At 110 lsa and the lash set tight -its very L88 like or, at least NOT STOCK. ( Used to have the Crane dual pattern L:S6 grind in there, now that was a stock solid lifter idle. 13-14" Hg at idle of 850 rpm. ) I have no doubt the 108 lsa version of the A3, lashed tight for higher revs', would idle very similarly to an L88 grind.

:D wumpita-wumpita-wumpita - nice but not if its a "stock" 435 hp effort.

L-71 I dont want to steal your post but went Harold gives his advise is always good inf. ;)

Harold this cams are roller or solid flat tapped ??
The 510 BHP in the 402A3LUN cam = rear tires HP ?? :eek:

smile.gif No flywheel HP, and they are solid flat tappet cams, not rollers.

Harold thanks for your time I am sure you are very busy. Currently the car has 3,000 stall, a stock tank with a sump, a holley blue pump feeding 1/2 fuel line and #8 AN to the carb. I was stronly considering using the 402A3. How much comverter do I need for that cam?

Gene,

Did you ever get the Summit Catalogue you were looking for?

Also I am not worried about vacuum as the car has manual drums.

The 3000 converter should be just fine, but if you notice a flatness to the power curve on the top-end, you will need a 2nd Holley Blue.
Put them in parallel, both going into a Y-Block and your #8 line. Also use another Y-Block with both regulators on the 2 exits. This is generally good for .1-.15 in an 11-sec car, more in a 10-sec one.

UDHarold