Guys, I'm trying to help a buddy put together a combo for his full bodied '71 Chevelle. The plan is to get to mid 11's with a 468 that will also be driven on the street...say a 50%/50% car. 3.73 gears. Trying to talk him into bitting th ebullet on an ATI Treemaster.
As with most everyone here, he does not have an unlimited budget.
Here is the combo we are contemplating at the moment...
2 Bolt #512 block bored .060
Steel GM 4.00 crank
Polished truck rods with 3/8 ARP bolts
TRW #2465 pistons
..now, here is where we need to make some decisions...
Because of the price and past good experiences with their tech dept. I called Howards Cams and for an "off the shelf grind", they recommended their 282/290(248/254) .665/.679 solid roller on a 110 LSA. But, in their catalog it says that cam needs 11:1 compression.
I also noticed they make a 285/285(244/244) .645/.645 roller that appears to be their version of the Comp Cams 288R.
Which would get the job done?
Now, do we do a port and valve job on the #049 heads he already has or do we try to pickup a set of oval Merlin's? The Merlins flow better out of the box but, is there justification for spending the cash?
And finally...he has both a Team G oval port intake and an Air Gap oval to choose from.
What to do?

I'm running stock 049's with 2.19/1.88 valves, 10.5-1 compression,alot less solid flat tappet cam, Performer RPM intake and 3.73's and best pass last weekend was 11.85 off the throttle. So I'm thinking with the cam your choosing and port work on the 049's, you are there easy enough. My new comp cam is similar to the cam you mention,only on a 107 LSA, peakier torque in a narrower rpm range.

Robert, what cam and intake are you running?
What kind of street manners with a 107 LSA?

I am currently running a Lunati solid 548/559 300/310 232/239 off the top of my head...currently the performer rpm intake,,not the air gap...My new cam will have the 107 LSA,I'm sure its going to be pretty choppy,but the 505 cubic inches ought to mellow it out some,new motor will be done 12/15. The 288 on the 107 is the one Ed used to run mid 10's,but the trick is gettin it to hook.

The only real down side to the Merlins is their weight...I'm told there substantially heavier than a stock GM iron head...guy told me almost 15 lbs a piece heavier which sounds a bit extreme to me, but I've never weight compared to the two to know for sure.

Either head will work fine.

Spend some time on the 049s, plus you can ( and will have to ) mill them to get your desired compression. FOr those heads I'd try the bigger split pattern cam you mentioned. DUal plane for any street duty, I;d say, but at the track it's anyone's guess!

BTW, do you solid roller types use hardened seats? Is it preferred to? Robert, did you upgrade the \seats on your 049s before you put roller pressures to them? Just curious. ( I had planned on just using the stock iron seat for my 049s).

I'll rip!

Originally posted by 427L88:
Spend some time on the 049s, plus you can ( and will have to ) mill them to get your desired compression. FOr those heads I'd try the bigger split pattern cam you mentioned. DUal plane for any street duty, I;d say, but at the track it's anyone's guess!

BTW, do you solid roller types use hardened seats? Is it preferred to? Robert, did you upgrade the \seats on your 049s before you put roller pressures to them? Just curious. ( I had planned on just using the stock iron seat for my 049s).

I'll rip! =

Gene,
The high roller spring pressures have almost nothing to do with the seat or valve life, it is the lack of spring pressure & loss of valve control that will flat destroy parts.
If your valves follow the cam designers intended path they will be set on the seat not dropped from a foot away ;)

My preference with a roller is to ALWAYS err on the high side of spring pressure & use a good lifter.

If my goal was mid 11's and I had the choice of those parts,I'd use the Howards 282/290,the 049's,and the RPM Air Gap,and not worry about the compression.
I'd spend some money on a good convertor,and make sure the car has fresh slicks or some kind of DOT's and aim for a 60 ft. in the mid-low 1.6X and you should have easily have mid 11's,consistently too-and I'm sure it's "best" might surpass your goal by a tenth or two if it's dialed in very well.It would also be a reasonable driver on the street,and those 3.73's would help that and certainly not slow the car down ET wise.
Bob,good luck with your 505 build graemlins/thumbsup.gif
That 'ole strong running 454 you currently have in your car still runs the number after all these years too..gotta love a motor like that :cool:

Thanks guys...all sounds good to us.
If I purchase the 509 that I mentioned in my other post, we will build this 468 and try all the components stated earlier. If not...heck, I may just build this combo for my own car! Who knows? But, the attraction of 509 cubic inches is hypnotizing!!!

WARNING on those pistons! They have p/v clearance problems, I have merlin ovals on my 468, I shaved them .030 to get the compression up to approx 9.7 & with thick blue head gaskets I still had to cut .050 valve reliefs(intake) into the pistons. I also had to retard my cam a few deg to make more p/v clearance.

I called TRW tech & they said to cut no more than .050 due to the thickness of the piston.

My cam has .549 lift & I sure wish I could advance it more.

Do a search for that part# on team chevelle, others have had the same problem, you might be looking for a different piston.

Gene, the 505 and roller setup will be using 781 heads and no sir,they don't have hardened seats. My son is going to freshen the current motor and install it in his 82 Cutlass.

I think the 468 deserves the Merlin heads. They woke up my motor after I destroyed my 049 heads, which where worked as much as possible.

Try and sell the 049s, you'll have better luck selling them as new/used, rather than already worked on.

Originally posted by mr 4 speed:
If my goal was mid 11's and I had the choice of those parts,I'd use the Howards 282/290,the 049's,and the RPM Air Gap,and not worry about the compression.
I'd spend some money on a good convertor,and make sure the car has fresh slicks or some kind of DOT's and aim for a 60 ft. in the mid-low 1.6X and you should have easily have mid 11's,consistently too-and I'm sure it's "best" might surpass your goal by a tenth or two if it's dialed in very well.It would also be a reasonable driver on the street,and those 3.73's would help that and certainly not slow the car down ET wise.
Bob,good luck with your 505 build graemlins/thumbsup.gif
That 'ole strong running 454 you currently have in your car still runs the number after all these years too..gotta love a motor like that :cool: i have to agree 100%. although the power producing potential is greater with the Merlins, they are not a necessity to reach your goal, thus money saved towards some good tires and suspension parts if needed. ;)

I had a similiar setup in my 70(before the small block). 454, chevy ovals with vlvs and bowl work, 10:1, 3:73s, airgap w850dp, crower solid roller 252/254 @50 on a 112-lsa, street flighter 10 inch, 3900lbs with driver, it ran 11.6s @ 115mph with a best of 11.59. I only ran it a couple of times before starting another project, so I really think it had more in it.

I tend to disagree here about the Merlin ovals b/c after you factor in all the machine work needed costs to bring them up to the about 269 cc's or so which will grow a schosh with no more then a mild bowl clean up and dingle-berry casting flash removal, you will have decent change towards a payment on the Merlins AND you will have a new/better head too, after it is all said and done...

As alway's, jmho...

BUT if I had it to do over again, I would buy a set of aluminum Canfield 310'ers for the weight savings alone b/c they, to me, are good value!!

pdq67

Guys, thanks for all the good info and opinions.
Looks like we may try the #049's and an Air Gap.
Do you think we should use the TRW 2349 closed chamber pistons with the #049's instead of using the TRW 2465's? If there are piston to valve clearance issues with the cam, we definately need a piston dome that can be fly cut(notched).

Using the TRW L2349F60 with 781 .225/.188 Cam solid roller Lunati 630 lift/dur@50 244/255 112CL Victor Junior 850 HLY 3500 stall 410 gears.
Street maners are tame.Timeing 34 by 2800rpm Vac 11LBS in drive.I use 89 pump gas. Responce hang on and go. No v/p clearnce prombles using MR gasket Ultra seal Head Gasket .039 compressed

ratengine, do you take your car to the track? What kind of timeslips you get with that setup?
Also, noticed you went with a single plane...any reason?

Just a street car. Tracion prombles woes. I just have tons of fun with this setup. Many hours of tuneing cam changes tried different carbs also intakes. I use the victor with 1/2" 4 hole spacer holley 850 with 4 corner idle helps getting carb to idles @ 900RPM.Hookers 2" with full 3" exhaust.I had the Perf RPM good intake but my car runs better with the victor.Sinks you in the seat.Dont beleive all you read about single plane intakes set up right,they work.With me + 3 more passangers off idle can light the tires.Driving at 40 punch it still lights up the tires.Go with the 225 int 188 exh valves on oval ports.I matched the intake ports to gasket and exhaust.After heads were cut for bigger valves,bought them home and clean up flash from bowls,ported only 1" back into ports,all done at home.Tuneing with 1 change at a time and if you get up set take a break and walk away come back to with a fresh head.Good luck