71 OLDS

I have a 1970 Cutlass Supreme that just got a rebuilt Brian Trick 3.90 rear and a built 2004r from Extreme automatics. I will be adding 1 ¾ headers and 2 ½ exhaust with an X pipe next. After that I want to do part one of my motor rebuild. The motor is the original 350 motor with 50k original miles on it. The heads have never been taken off but the original build sheet shows it was a 2BBL so unfortunately it should have the LC 14 cc dish pistons in it. The previous owner added a performer (3711) intake, 3712 performer cam, & an Ebrock 600 carb.

My plan was to do a "top end only" for part 1: Ebrock heads, RPM intake, 750 Ebrock carb (I'm a QJ guy but the cable that allows my 2004R to be adjusted only fits these Ebrock carbs. It took FOREVER to get this trans "dialed in") and a new cam. I was going to run the car for a while with the stock bottom end keeping the RPMs at or below about 5200. The Ebrocks would be cut down to 60 ccs to give me around 9.4 measured CR (with the stock -14 cc pistons). I understand the heads will have to be matched to the RPM and I'll have to work out a solution for the manual fuel pump or go electric.

"part 2" would be pulling the motor and doing a full and proper rebuild going with a 375 stroker motor (4.125 x 3.5) and a hyd roller cam (BTR Special) . Because of the expense of doing this, I wanted to get the heads and intake paid for in part 1. I wouldn't want to try to do everything in one shot because of the overall cost. I would guess it would be 6 months to a year of driving with part 1 until I could afford to do part 2.

My questions are:

1.. How would the Ebrock heads, RPM, 750 Ebrock carb and a cam like the Erson TQ40 run with 9.4 CR and the stock bottome end? I understand this is not ideal and 10:1 would be better with the aluminum heads but I THINK I should be OK especailly with the 3.90 rear and I wouldn't want to go any more then 60 ccs on the heads. If I keep the RPMs at or under 5200, would I be OK with the stock oil setup too? I would prefer to hold off on upgrading to the 7 qt pan until part 2 if possible. I'm sure I will give up some power that the heads could provide at a higher RPM and I'm OK with that. I just want to make sure the car will run OK with this and if I don't get too crazy with it I'm hoping the stock bottom end will stay together.

2. For part 2 when I pull the motor and go with the 375 stroker build up with a mild hyd roller will there be any issues going with something like a 15 cc custom dish piston? I won't be able to go with anything off the shelf with the 4.125 bore and with the 60 cc heads I'm going to have to have a pretty big dish to keep the measured CR at or around 10.1 or so (for pump gas). I see most guys are running flat tops or small dish pistons with the higher performance builds. Assuming I run a zero deck and .040 gasket is there any negative to combining that with a 15 cc dish piston besides the cost of the custom piston?

Sorry for the long post. Thanks in advance for any comments or feedback.

-Joe

71 OLDS

Here's a pic of the car:

driverside2.jpg

and the motor:

engine2.jpg

507OLDS

You might want to compromise on milling the heads less,and having less compression now,then run a smaller dish or flat top piston with the 375".Maybe 8:5:1-9:1 for now.

cutlassefi

The TQ40 will be fine with 9.0:1 or better, just advance it 4 degrees.
I agree with Brian, you may want to not cut the heads too much to begin with. But on the flipside you shouldn't have a problem finding a dished 400 Chevy piston. That will be your best option on the stroker build.

Not sure what Bill will charge to do your work but there are other options, while still having quality work.

71 OLDS

OK thanks guys. So I'm guessing that means you both think 60 ccs is too far on the Ebrocks. The problem is to go 9:1 now I would still have to go 64 ccs for part 1 and then about an 11 cc dish custom piston for part 2. Does that small change make both "more acceptable"?

How far is too far for milling the heads? What's bad about 60 ccs vs 64 ccs assuming that's how much less they should be milled?

Thanks!
-Joe

71 OLDS

I had another thought. I'm not a big fan of the Ebrock 3712 cam but the motor currently is 8.55:1 and is running well with this cam.

(4.057(stock bore)/3.385(stock stroke)/70/-14/ .052(.024 down+.028 gasket) = 8.55:1 CR

What if I only milled the Ebrock heads to 69 ccs (about the same as the #6s now) add the RPM and the 750 Ebrock carb and leave the current cam in there? This would put me at 8.63:1 CR.

Here are the specs on the 3712 performer cam: 280/290, 204/214, 448/472 114/106

Would the car still run OK with this set up for a while? Seems like kind of an odd combo but maybe it would be OK. Would the 750 Ebrock carb be too much for this interim setup? Should I leave the 600 on there and hold off on the 750 carb until I go with the 375 build up?

A 69 cc head would allow me to run a 6 cc dish piston with the 375 build up and be about 10.15:1 - (4.125(.068over)/3.5(stroke)/69 ccs/-6/.04(zero deck+.04 gasket) = 10.15 CR

507OLDS

Put them at 70cc and stop.Good enough.Run the cam that is in there.No need to buy & install another cam,only to have to buy a 3rd cam when the 375 is built.I know Bill,or anyone else that would build the 375,will want a different cam,just for that combination.If the heads need milled more,when the 375 is built,then they can be done at that time.

71 OLDS

OK thanks Brian. Makes sense. So part 1 would be:

original 350 (50k miles)
stock bottom end
Ebrock heads milled to 70 ccs
RPM intake
3712 performer cam: 280/290, 204/214, 448/472 114/106
8.55:1 CR
3.90 rear
2004R trans
1 ¾ headers
Will shift around 5000 – 5200 RPM

What about the carb? Can I put the 750 Ebrock on with this setup or should I just stick with the 600 Ebrock I have now and add the 750 for the next part?

507OLDS

Leave the 600 on there.

71 OLDS

My headers and exhaust are finally done.

fullexhaustpic.jpg

Here's a video that shows the engine compartment with the new headers, my new open aircleaner set up with the olds foam (no breather), and the new aluminum radiator:


Doing some more adjustments and maybe a new converter for the trans next.

I'm getting close to being ready to buy the Ebrock heads & RPM intake as part 1 of my build up described earlier in this thread. I've decided to only have them milled down to 73 CCs so I will be at around 10.2:1 CR with the stroker build up for part 2 using BTR Bills suggested rods/pistons etc:
375ci -1.44 dish CP pistons, 6” H Beam SBC rods, 73 cc Ebrock heads =(4.125(.068over)/3.5(stroker)/73 ccs/-1.44/.04(zero deck+.04 gasket) = 10.21 CR

The negative to this is my CR will actually be decreasing to about 8:5:1 with the 73 CC Ebrocks (vs. my stock #6 heads) and that includes going with the .011 shim gaskets.

Since it may be a year or more until the motor will be pulled for the stroker part 2 build up I'm hoping the car will drive pretty well even with the low CR. I was going to leave the 3712 performer cam (280/290, 204/214, 448/472 114/106) in there but I'd really like to put a different cam in for a little better performance during this inbetween stage. The low CR doesn't really go with the Ebrock heads, RPM intake, AR 1 3/4 headers with 2.5" exhaust and X pipe, 2600-2800 stall (may be adding next week) on a built up 2004R with 3.90 gears so I'm hoping to find a new cam that would help with this.

I believe the tighter LSA would help with the 8:5:1 CR and is better with good flowing exhuast so I should be OK there, but I've also read that tight LSAs are better with or help with poor flowing cylinder heads which shouldn't be the case even with out of the box untouched Ebrock heads. Based on that not sure if a 108 or 110 LSA would work best.

I'm thinking a cam like this Ultradyne:
272/276
217/221
515/515 (upgrading to 1.7 HS when I get the heads)
108/104 or 110/106

might be better then the 3712 during this temporary stage but looking for feedback/suggestions. I was thinking this would still give enough vacuum for the power brakes and AC, give more power sooner and help with the low compression with the 108 or 110 LSA vs. the 114 in there now. I only want to shift at 5200 at the most with this build. Was hoping to run 13s with this setup next summer.

Thanks for everyone's help and suggestions.

-Joe

captjim

Honestly, I see no real advantage in doing this in stages. You already acknowledge that the heads are a mis-match with the other components. With your engine being so low in mileage and I'm assuming running good, why not get another 350 block ($75 or free), do up the stroker, have it ready to drop in, and sell your running 350 ($300-$500, depending on location) or keep it as a spare, in the event you have major issues. In fact, let your builder get the core and save you the shipping cost and hassles. Your 350 is not going to run noticeably better with the E-brock heads, it may even run worse. You can then use flat top pistons (better flame travel) and won't have to cut the heads as much, if at all. More $ saved. Just some thoughts....

71 OLDS

Captjim, the ONLY reason I'm doing it in stages is to spread the cost out.

Ebrock heads = $1,800 + $175 to mill = $1,975
RPM intake = $350 + $200 for port matching = $550
Harland Sharp 5017 = $353
Total = almost $3,000.

The stroker build up without this $3k is a ton of money. It would really help to have this part done and paid for first.

I understand I may not get much performance gain out of it if any but that's why I'm trying to figure out if there's a cam that would help the cause a little. If not the car is a blast to drive right now so if it stays the same it's not the end of the world. It would be painful if it drives worse though. If that's the case I'll have incentive to get the part 2 build up done even sooner.

Also the plan is to keep the orignal block for as long as it lasts and use it for both part 1 & part 2.

captjim

Put the money in the bank or buy a 1 year CD. It just seems silly to waste the money on the cam, head milling, gaskets, pushrods, fluids, etc. Add those costs plus the value of the running engine and you are getting close to a grand. Also, they used the same block on every 350 from 68-76, who cares if it is the original, the stamping will be correct.

71 OLDS

That may be a sensible/logical way to do it and could have been an exact quote from my Dad by the way (also named Jim), but really not the way I want to go. I'm trying to progress along each car (my 71 442 and my son's 70 Supreme) as best I can little by little. Spending $10k+ in one shot on the Supreme's motor is not going to happen. Doing it in several stages helps me NOT think about how much I'm actually spending. Also I was hoping to get some of the smaller items done inbetween the 2 parts of this build up (fuel pump, fuel lines, MSD 6 AL, battery to trunk, new shocks, AC conversion etc etc) and maybe get a few track runs in with my son along the way too.. I appreciate your thoughts and feedback though. You've given me some new ideas to consider.

Anyone have any input on what cam might help my cause here if I stick with my original plan?

Thanks!
-Joe

71 OLDS

Below is the build that made me think about putting the new cam in for my part 1 top end build. This set up is similar to what mine would be except with Ebrock heads. This is also what made me research the tighter LSA for the low compression. The cam I'm thinking about is one smaller then the one used here:

captjim

It is probably fine, but again, why spend $300 on a cam and lifters that you are going to ditch in a year? FWIW, I had a 16-18 Engle 210/216 .472/.488 on a 112 in 2 350s with high 8.xx to 1 CR and both ran very good.

71 OLDS

I had an opportunity to talk to Cutlassefi (Mark) about my plans. Long story short I'm leaning towards (hopefully) a longer term part 1. What I mean is the Ebrock heads will be milled a little more for about 9.3 CR for part 1, the car will be driven like this for several years (assuming the bottom end survives). This will provide lots of time and a few summers at the track to get many of the "add-on" projects completed and dialed-in (fuel pump & fuel lines, carb, drag radials or slicks, battery to trunk, brakes, shocks/springs/airbags etc). This will also mean I will need a dished piston for part 2 (stroker build) and I'm OK with that.

Because of the good flowing exhaust (new AR 1 3/4 headers and 2.5" x pipe and exhaust), the good flowing heads (out of box Ebrocks but still good flow for a 350) and because I want to "protect" the stock bottom end as much as possible, and only shift at 5200, Mark suggested a single pattern cam. We need a cam that is "all-in" at about 5000, I need to have vacuum for pwr brakes, and will be running stock AC.

Based off all of this, Mark suggested a cam around .220 @.050 on a tight LSA 108 or 110 to keep the power down low. He suggested the:

Erson Hi Flow AH cam 284/284,220/220 @ .050, 535/535 (1.7) it comes on a 110 LSA but if I can get enough vacuum for my brakes on a 108 that might even be better.

A similar cam I found searching around is the Isky 270H cam:
Isky 270H cam 270/270, 221/221 @ .050, 515/515 (1.7) on a 108

This Isky is popular with the 350 chevy guys because of the idle and still being able to run pwr brakes. There are several youtube videos of guys cars idling with this cam. Here's one example:

You Tube

I'm not one to buy a cam for the idle sound but I have to say it sounds pretty good.

So if I go with this plan, the details would be:
1970 Supreme

original 350 (50k miles)
stock bottom end - untouched
out of box Ebrock heads milled to 64 ccs
Harland sharp rockers 5017 (1.7)
RPM intake (matched to heads)
Ebrock 750 carb or 750 QJ
CR 9.3:1(4.057(stock)/3.385(stock)/64/-14/.037(.025 down+.011 steel shim gasket from smitty)
Erson Hi flow AH cam 284/284,220/220 @ .050, 535/535 (1.7) 108 LSA
or
Isky 270H cam 270/270, 221/221 @ .050, 515/515 (1.7) 108 LSA
3.90 rear
2004R trans - set to shift at WOT at 5200 RPM
2600-2800 converter
AR 1 ¾ headers w/2.5" X pipe and exhuast
28" drag radials or slicks
3850 lbs w/driver

I know its' an odd set up and these 2 cams are pretty "old school" but I'm hoping the car still has great throttle response and is a good driver. I'm also hoping I could run some mid to low 13s at the track with a little testing and dialing-in.

As always feedback is welcome - good or bad. Haven't purchased anything yet but pretty sure this will be the way I go. Would like to get all of this done over the winter.

-Joe

captjim

Sounds like a pretty good combo. You don't need to twist Olds engines up, guys laugh when I tell them my best ET (13.9) with the 210/216 cam came shifting at 4600. I am a big fan of short-shifting in a heavy car, especially the 1-2 shift. Low-mid 13s is a reasonable goal and when you rebuild the bottom end you can re-use the cam and other components. The gear should make up for any laziness (if there is any) down low. I would go Q-jet or Holley, personally not a great fan of E-brocks though other guys are happy with them. I had vapor lock and other issues at the track with mine.

71 OLDS

Jim,

Thanks again for all your feedback. Both you and Mark have been helpful with your comments, suggestions, and information. Mark said the same about the Ebrock carbs. I'm a QJ guy myself. That's what i have on my 71 442 but it's got a 5 speed manual trans. The only reason I would go with the Ebrock carb is if I have to use the Bow-Ties TV cable with my 2004R. It's a life saver right now on my 600 Ebrock to soften the granny shifts on my built up trans. I have it on the loosest setting (where it's still OK for the trans) and the granny shifting is still really violent. I'm upgrading from the current 2200-2400 converter to a looser 2600-2800 converter in the next few weeks and I'm hopeful that will soften those shifts. If so I can have a "non-adjustable" TV cable put on my 750 QJ. They don't make an adjustable one for the non-chevy QJ carbs.

-Joe