Help with 355 - Chevelle Tech
Performance Our High Performance area

 7Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 29 (permalink) Old Aug 24th, 19, 8:14 PM Thread Starter
 
Join Date: Mar 2019
Posts: 23
Help with 355

First I want to thank everyone for the wealth of knowledge I have received from reading all of the different threads on this forum. This forum has allowed me learn so much. I cannot thank everyone enough!
I purchased a 72 Chevelle with a 355, 400 turbo transmission and 10 bolt rear end. I was not given very much info about the car except that it was built for the drag strip, had some aftermarket cam, and the transmission had a shift kit.
I have done a lot of work to it. I’m trying to get it more of a street car, but still with as much torque and speed as I can. I rebuilt the rear end with 3:73’s, Yukon DuraGrip, Motive Axles and an aluminum rear girdle. It had 4:11’s and the spider gears welded. I also rebuilt the Holley Double Pumper. I have no clue what cfm it is. But, I’ve had a terrible time getting it tuned correctly. The car had a noisy gear drive that I had to get rid of, so I put a double roller timing chain on. It drove me nuts. After installing the timing chain, I was able to actually hear to motor and thought it was missing while I was trying to get the carb tuned. I got it good enough for the time being because I ordered an Edelbrock Performer RPM Airgap intake. I figured I would check the cap and rotor, which is a pro billet MSD powered by a 6AL box and Blaster 2 coil. It was very corroded, so I cleaned it up and put it back on and the car wouldn’t start. It backfired and the carb had a small fire in it that went out very quickly. I replaced the cap and rotor and still no start. I checked for spark with an inline tester and it was an orange, so I figured maybe a weak spark and replaced the coil. Still nothing. I’m thinking maybe the pick up is bad? I checked and the rotor is pointing to the #1 cylinder at TDC. I pulled the distributor and it looks fine except for some corrosion on the pick up. Anyone have any thoughts or ideas on this?

With the new intake on the way and the distributor already out, I just pulled the Victor Jr. that is on the motor. I’m replacing it because I don’t think I need the 3,500-8,500 rpm range for mainly street driving. I found out that I have the “Turbo” 340292 heads with 1.6 intake and 1.5 exhaust valve roller rocker arms. They look aluminum and pretty new. It looks like the heads were made in the 70’s, have a 64cc combustion chamber, 2.02 intake and 1.60 exhaust valves. My question is should I just replace the camshaft with a new one that I know the actual specs of? At idle, I was getting tops about 8” of vacuum. The vacuum gauge was never consistent. I’m wondering if the intake had a vacuum leak because I couldn’t find one anywhere or maybe it was just the cam. I don’t think the cam sounds that aggressive. If I replaced the cam, what would be a good one to get with the “Turbo” heads, Airgap Intake (1,500-6,500rpm), Holley Double Pumper, 400 trans (shift kit, stall converter at or a little below 3,000rpm) and 10 bolt 3:73 posi rear end. I would like it to match the 1,500-6,500 rpm range of the intake and be good for as much street performance as possible. I’m not concerned about the lopey sound. Are there certain specs I should be shooting for?

I look forward to receiving some feedback for all of this that I have going on. I truly appreciate everyone’s help!! Again, thank you!!
JerseyDevil5 is offline  
Sponsored Links
Advertisement
 
post #2 of 29 (permalink) Old Aug 24th, 19, 9:20 PM
Tech Team
 
Join Date: Feb 2019
Posts: 323
Re: Help with 355

I ran some 292 Turbo heads through the 90's that i ported and they were ok. After I found they had some cracks I decided to do some other heads and re-did a set of Bowtie heads. Car picked up .2 tenths and 3mph with just the heads switch. Changed out the cam and intake and went even better. The 292's were good in their day as were the Bowtie heads. Out of the box 062 906 Vortecs are as good as both those sets of heads.
68Chevele is offline  
post #3 of 29 (permalink) Old Aug 25th, 19, 8:48 AM
Lifetime Premium Member
Jeff
 
Join Date: Jan 2002
Location: western ma.
Posts: 558
Re: Help with 355

What pistons are in the engine? You'll need to know what your compression ratio is and also how much lift the springs can handle and their pressures before putting a different cam in it.
nitrofox is offline  
 
post #4 of 29 (permalink) Old Aug 25th, 19, 2:27 PM Thread Starter
 
Join Date: Mar 2019
Posts: 23
Well after starting to clean off the old intake gasket, I looked into the heads and saw these areas. They are right where the stud goes into the head for the valve covers. Would you guys say it’s time I start looking for new heads? I’ve been chasing a vacuum leak. My vacuum gauge bounces consistently between 5-10”. It never stays at a set reading. But, I was thinking the low vacuum was most likely from the cam. Any thoughts or ideas?

Also, I have no idea what pistons are in the motor. Everything has been a surprise so far. Thanks!
Attached Thumbnails
Click image for larger version

Name:	DF407EDF-8C2B-4F7D-94BC-C7480FA35CB9_1566757320105.jpg
Views:	40
Size:	62.0 KB
ID:	601488   Click image for larger version

Name:	A1E7063E-A3B5-4374-9F6B-B99D64DE9D3E_1566757347136.jpg
Views:	38
Size:	102.1 KB
ID:	601490   Click image for larger version

Name:	2CB889D0-C1A7-417A-8589-13BB5A01A41D_1566757375839.jpg
Views:	30
Size:	53.3 KB
ID:	601492   Click image for larger version

Name:	CF993A67-E7A2-4361-AA45-2A50A2292B18_1566757405474.jpg
Views:	28
Size:	72.9 KB
ID:	601494  

Click image for larger version

Name:	F9CBAC76-08F8-4018-B776-7C3D17C49ECD_1566757431843.jpg
Views:	30
Size:	35.0 KB
ID:	601496   Click image for larger version

Name:	9A918BAF-A539-4DA7-989D-7ACF9793D18E_1566757464834.jpg
Views:	27
Size:	73.6 KB
ID:	601498  
68Chevele likes this.
JerseyDevil5 is offline  
post #5 of 29 (permalink) Old Aug 25th, 19, 3:16 PM
Lifetime Premium Member
Tom
 
Join Date: Oct 2006
Location: Firestone, CO
Posts: 1,037
Re: Help with 355

It will be tough to keep a gasket intact between those intake ports. Eek.

70 Camino...Roller

69 Malibu Stock 307, Reverse Manual TH350, 4,500 Stall Edge Converter, 4.56 Spool 35 Spline 12 Bolt

76 C20 VortecPro 496 628HP 655 lb/ft TH400 Edge Converter, 4.10 14 bolt
Tommy the Cat is online now  
post #6 of 29 (permalink) Old Aug 25th, 19, 3:44 PM Thread Starter
 
Join Date: Mar 2019
Posts: 23
That’s kind of what I was thinking. Any recommendations on heads? I have heard good things about Vortec heads. But, I just got the Airgap intake and new valve covers in that have the 16 bolts for the intake to the heads and perimeter bolt valve covers. I guess I could always return them. I’m looking for something that will give me the most torque and horsepower for the street without breaking the bank. At this point, I should just replace the camshaft to match whatever heads and intake I end up with. Kind of a disappointing day!
JerseyDevil5 is offline  
post #7 of 29 (permalink) Old Aug 25th, 19, 4:37 PM
Lifetime Premium Member
Beth
 
Join Date: Oct 2010
Location: Nashville TN
Posts: 1,433
Garage
Re: Help with 355

Go to Team Camaro and ask those guys about small block heads in the Engine section.

I think Patriot gets recommended a lot. They know where the best bang for the buck is.

For a street roller cam, don't go much over 220 degrees on the intake @ .050" lift.
Chevelles are heavy and you need torque.

Chris Straub recommends about 10 degrees more on the exhaust, so a cam of 224 intake - 234 exhaust would be the most I would get.

67 Chevelle convertible, 138 vin, original 4 speed, bucket seats, Marina Blue with black interior
nashville beth is online now  
post #8 of 29 (permalink) Old Aug 25th, 19, 4:42 PM
Senior Tech Team
Justin
 
Join Date: Dec 2016
Location: Huntington Beach
Posts: 1,115
Garage
My sbc 358 is Brodix IK180 heads which I ran with the air gap intake. Hyd roller 221/235 .510/.510 but I’m running 1.6 rockers so it’s .544/.544. Hauls the mail if you could swing it I’d go with profiler 185 heads or afr 180 heads

1974 chevelle with 73 laguna nose sbc 357 Brodix IK180 heads Comp Cams XE274H Edelbrock RPM airgap 650 AED double pumper, M20 muncie, Truetrac with 3.73s
JF74chevelle is offline  
post #9 of 29 (permalink) Old Aug 25th, 19, 4:46 PM
Senior Tech Team
 
Join Date: Feb 2000
Location: SF Bay Area
Posts: 9,857
Re: Help with 355

What sort of budget are you working with?

Keep in mind whether or not you want to reuse your rocker arms, as you already know, the intake isnít compatible with the Vortec heads, neither would the rockers. I think there are aftermarket Vortec style heads available with conventional intake bolt patterns. Its worth scouring Summit, Jegs and other online parts suppliers. Iíd pull the heads and try to figure out what pistons you have before making a decision on new heads.

Good luck with your decisions.

Steve R
Steve R is online now  
post #10 of 29 (permalink) Old Aug 25th, 19, 4:54 PM
Lifetime Premium Member
Beth
 
Join Date: Oct 2010
Location: Nashville TN
Posts: 1,433
Garage
Re: Help with 355

Just went to TCamaro and I think this would be your best deal ($907) :

https://www.summitracing.com/int/par...make/chevrolet

The edelbrock e-street heads come in 64 and 70 cc chambers so choose the one that works with your pistons.
Kirk's67SS likes this.

67 Chevelle convertible, 138 vin, original 4 speed, bucket seats, Marina Blue with black interior
nashville beth is online now  
post #11 of 29 (permalink) Old Aug 25th, 19, 5:45 PM
Tech Team
 
Join Date: Feb 2019
Posts: 323
Re: Help with 355

Quote:
Originally Posted by JerseyDevil5 View Post
Well after starting to clean off the old intake gasket, I looked into the heads and saw these areas. They are right where the stud goes into the head for the valve covers. Would you guys say itís time I start looking for new heads? Iíve been chasing a vacuum leak. My vacuum gauge bounces consistently between 5-10Ē. It never stays at a set reading. But, I was thinking the low vacuum was most likely from the cam. Any thoughts or ideas?

Also, I have no idea what pistons are in the motor. Everything has been a surprise so far. Thanks!
I hate when people hog the port opening out thinking they will get more air flow, what you can do is buy a felpro 106 gasket and glue it to the port with the yellow sealer, then trim the gasket and use some sealer on the intake and let it dry for 24 hours. The area at the top of the port is just the valve cover stud, I always epoxy them in and smooth them over with the sanding roll. If they are not cracked and seeping water in the ports or oil run'em.
jeff swisher likes this.
68Chevele is offline  
post #12 of 29 (permalink) Old Aug 25th, 19, 5:46 PM Thread Starter
 
Join Date: Mar 2019
Posts: 23
Thank all of you very much for your help!! I started the search online and in my catalogs. I’m going to look into every recommendation each one of you have made. The current heads have a 64cc combustion chamber, so I assume that is what I would need. I am definitely factoring in new rocker arms. Right now they are 1.6 and 1.5. I’m considering the Edelbrock Top End Kit with the Airgap intake, Performer RPM heads with hydraulic flat tappet cam, lifters and all bolts/gaskets included. It claims 410 hp. It’s $2266.95. I could return the Airgap that I just got delivered. I would be able to keep my new valve covers since this would not be Vortec heads. I’m trying not to go over that price point. Any thoughts on this setup?
Kirk's67SS likes this.
JerseyDevil5 is offline  
post #13 of 29 (permalink) Old Aug 25th, 19, 6:22 PM
Lifetime Premium Member
Tom
 
Join Date: Oct 2006
Location: Firestone, CO
Posts: 1,037
Re: Help with 355

Looks like the rockers are stainless rollers. I'd use them if they're smooth and tight. The Edelbrock top end would suit your combo well.

70 Camino...Roller

69 Malibu Stock 307, Reverse Manual TH350, 4,500 Stall Edge Converter, 4.56 Spool 35 Spline 12 Bolt

76 C20 VortecPro 496 628HP 655 lb/ft TH400 Edge Converter, 4.10 14 bolt
Tommy the Cat is online now  
post #14 of 29 (permalink) Old Aug 25th, 19, 6:42 PM
 
Join Date: Feb 2019
Posts: 17
Re: Help with 355

Quote:
Looks like the rockers are stainless rollers. I'd use them if they're smooth and tight. The Edelbrock top end would suit your combo well.
If I'm a betting man, based on what you got from the previous owner and the parting lines I see on them, those are the Crane silver rockers - which are ABSOLUTE GARBAGE (in my personal experience); you'd get more power out of those by selling them for scrap metal value. This is going to sound harsh and overboard, but I personally would use a stamped GM rocker over those things...

(Ok, maybe not, but it would be close.)

There's plenty of other good rocker options out there given a little bit of web searching and archive searching here. Your thought on the Edelbrock route isn't bad either for what your budget sounds like.
Bronze68 is offline  
post #15 of 29 (permalink) Old Aug 25th, 19, 9:04 PM
Team Member
George
 
Join Date: Feb 2010
Location: Upper Sandusky, Ohio
Posts: 2,561
Re: Help with 355

No way that top end kit is 410hp...I have those heads, ran them on my 355 with 9.7:1 comp, clay Smith hyd roller (221/235-.510 lift)...280 hp at the wheels. Ran good, drove good. But no way with their cam it would do 410hp.

Still have the heads on my current 383...now ported a bit with much bigger solid roller, more compression etc...335 hp at the wheels. On both motors they were done around 6000rpm. For a street car they are decent heads.

Those new Promaxx heads are worth a look.

'71 Malibu
3580 #, Carbed 6.0l LS swap in process
T-350, PTC 9" converter, 12 bolt, spool, 3.90 gears, MT ET R 275/60/15

355 [email protected]
125 [email protected]
383 Mud Motor- [email protected]
100 shot [email protected]
'72 Greenbrier Wagon: 454, 700R4, 12 bolt with 3.73
Geo71 is online now  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome