TWINRAY

I'd like to do Alum heads and a roller cam. I have a :o 3.08 rear but for cruising all day at 80. It's not gunna spin too high so I don't want to sacrifice any low end torque. Anyone feel like responding .

MelWff

Your best bet would be first change the rear ratio to something in the 3.36 to 3.55 area. The engine with the 3.08 and the automatic will fall on it's face with any cam changes.

MotorHead

First gear in an automatic is pathetic

TWINRAY

Well, thanks for your replies (). I know it's an auto but it's my Cruiser. I have my '67 with the 327/350 and 4.11 rear for tearing up the local sidewalks . Getting back on track - there's gotta be something I can do keeping it sorta as is. Any roller cam and new heads is going to give me another 40 hp right? That's all I'm looking for. I'm not changing the 3.08. I like 3 grand at 80

djcwardog

Staying with your desires, you need to be sure you retain as much low-end torque as you can. So skip the racer cams (anything at or above 268 duration) on this one, keep your compression ratio down around 9 or 9.5 to one (you have stock flat-top psitons in there...?) and put in a cam that gives you a BMEP close to making the motor ping (say ~160 or so). Play around with CamQuest6 (Comp Cams) or DD2000 and you will see cams like the lower two or three roller hydraulics sold by Comp Cams as possible for you. An XR270HR is likely too big for what you want, so look at the XR262HR or even smaller. The advantage to rollers is that they allow much quicker lifter rise on the cam ramps - more 'area under the curve." Of course at hese short durations, I begin to question the extra cost as being worth it - hence my own recent choice of a flat tappet hydraulic for my 454 - a Comp Cams XE262H. I really considered the XE256H as well but I have enough cubes that the bigger cam still works for what I wanted.

TWINRAY

. I was thinking alum heads for no other reason (well except for saving some weight) because by the time I bring the old iron heads somewhere to get a valve job and by the time the labor cost and the cost for (probably) some new valves, I might as well buy something all assembled ready to slap in. Thanks for the advice - it gives me a good start.
Fred

Z068

I'm in the process of a 68' frame off, Going retro, Turnkey Engine LS7 package. Against the grain of the forum, I'm going back with the TH400 and a 3:55. I feel the added mods to go with an OD trans are not worth just lower RPM's at highway speeds. Fuel mileage, who G.A.S.


Steve

ajrothm

Assuming the bottom end is very healthy, you need air flow through a small port, increased compression and some cam. Personally I would go with the Vortec heads. They are cheap, flow well for the small ports and will have good velocity at low rpms....lastly the small chambers should help bump your compression up to 9-1. You could mill them some and use a thin MLS head gasket to gain a tad more compression. Make sure you order the upgraded Vortecs that have been machined for larger springs so you can get a good matching set for the cam, maybe some beehives would be in order. You will also have to get the corRect rockers/push rods etc for the Vortecs but this stuff is cheap. For the cam I would definetly go hyd roller, something in the 224/228 range and around 480/490" lift. That setup combine with an RPM air gap intake(for Vortec heads and if you can squeeze it under your hood) should get you an honest 350-375hp at the crank once tuned.

You will want to get a good torque converter. Something that is efficient and tight until you nail the throttle....Probably an 11", 2500 stall. That will really wake it up out of the hole and allow you to keep your 3.08s for the highway. You will notice about a 200 rpm increase at freeway speed with the converter but not near as bad as a gear change would be. The key to the converter is efficiency. Don't get a cheapy or else it will be sloppy as hell around town and never lock up on the freeway. Stick with the good manufacturers here....(Ati, Coan, continental, Ptc, ect).


This combo will wake up your stocker all across the powerband and still leave you cruising down the hwy at 80mph...

trsulliv

I have a 73 auto that I put a ZZ4 crate engine into, and put a high stall converter into and a shift kit and it really didn't have much off the line. Then I converted it to a Richmond 4+1 manual and love it. It launches very nicely on the street, and has the right gears for Road America.

TWINRAY

Thanks all. I will take all your advice. More importantly, this week end I finally made some progress. I got the transmission crossmember back in with a new transmission mount. Today I got all the new body mounts in. Tomorrow I will tighten them up. Just have "to fuss" with the #4 and #8 mounts as the cages were rusted. I will probably run the bolts south instead of north - if you know what I mean. Then I can get the gas tank in and put back the trailing arms. :oSorry to go off topic but assembly is at this point a positive step. . But I want to get this motor issue sorted out. I also want to get the old heads off and see the wear on the cylinders. This car has had what I think is a pretty easy life. But if there is a lip on the top cylinder, it will get new ringsl We'll see what happens. Thanks to all and will keep you updated

TWINRAY

This is where I'm at now. I'm gunna pull the motor, slight overbore with new pistons, oil pump, rings, and bearings. Crazy not to do it. Got a buddy of mine advising me on a machine shop - he's got buddies who know that ***t, I don't . Heads will probably be between the AFR 180's or GM fast burn. Intake maybe the Weiand low profile (forgot the specific name). Should now be able to get the Trailing arms and rear halfshafts on this weekend and back to a rolling chasis .

c3corvette77

you can get one of those total power top end kits from trick flow or edelbrock. they include everything you'll need except the intake manifold and carb. they are in the area of $2k. worth a thought.