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-   -   Help me build a 355 sbc (http://www.hotrodders.com/forum/help-me-build-355-sbc-154821.html)

TiMeWaRp 03-11-2009 07:03 PM

Help me build a 355 sbc
 
Here's what i have [and would like to use if possible] 1974 350 4 bolt main block with stock forged crank, .40 over Speed Pro forged [L2256f] pistons and a Comp 292 cam. I need the rest - heads, rods etc. Will be in a 1972 Vega with a 3000-3400 stalled turbo 350 and a 4:56 12 bolt rear. Car will be a weekend toy that needs to run on pump gas [93]. Throw out your ideas or better yet combos you have run.

tinman386 03-12-2009 06:34 AM

I believe that cam needs a minimum of 10-1 compression to function properly so pump gas might not be in the cards. heads will need correct springs for that cam. As far as parts go remember you get what you pay for. And for the heads I would run a 194 valve or more likely a 202. I have a comp 280 cam on a motor I am working on with 9.7-1 compression and I am using 194's. Hopefully ive been of some help.

Jsup 03-12-2009 07:00 AM

Find three reputable engine builders and let them spec it.

Let me tell you a little story. A guy I know asked the same question. He took all the forum advice. When he got his car on the street, he had guys using "junkyard motors" beating him silly.

Just sayin. If you're going to do your research on the internet, double, triple check it.

ap72 03-12-2009 07:00 AM

Quote:

Originally Posted by tinman386
I believe that cam needs a minimum of 10-1 compression to function properly so pump gas might not be in the cards. heads will need correct springs for that cam. As far as parts go remember you get what you pay for. And for the heads I would run a 194 valve or more likely a 202. I have a comp 280 cam on a motor I am working on with 9.7-1 compression and I am using 194's. Hopefully ive been of some help.


I mean this in the most respectful way possible, but you can ignore most of that talk about valves. Its not as critical as many people think, especially if you don't do any porting. If you port the heads then it can begin to make a difference because you have to match the heads to the valves. You will need to get around 10:1 but it should run just fine on 93, especially in that light car with those high gears. There are a lot of head choices, so narrowing it down without what you're looking for is just a rough shot in the dark. You'll need a set of aftermarket ones if you can afford them, there's not really a stock casting that can keep up in those high RPMs, not even the almightly Vortecs (unless you spend a lot of time and money reworking them).

How much do you have to spend on the heads? Also, I'd recomend a Vic. Jr. intake with at least a 750 carb.

TiMeWaRp 03-12-2009 01:09 PM

I want aluminium heads for the weight savings. As far as $$ i'd like to spend 2k max, so i guess that will include a fair choice of brands.

It seems everyone jumps to AFR heads, i just want to see what some of you are running to get some real world numbers/reviews.

I would like to use the above parts, but if it would make for a better motor i'd put them aside. It seems that the L31 short block and a set of efficient heads and roller cam would produce more useable hp.

I guess i'm like everyone else, i want to build a stong streetable pump gas motor on a budget.

SS66chevelle 03-12-2009 01:24 PM

Respectfully, why not just buy a crate motor off of ebay from a reputable shop with a dyno sheet? a 20 second glance turned up 450hp 383's for about 4k.. if you want to spend less how about a 365hp 350 for $2600? my point is unless you're doing it for the fun/educational factor let the pros pick the engine parts combos, get a reliable motor with good power and papers to back it up..

ap72 03-12-2009 01:24 PM

If you wanta real streetable 475ish hp, then going with a 383 build out of a Vortec engine is very hard to beat. Torque out the ying yang and easy and relatively cheap to build. Looks like you could really use an aftermarket block if you plan on revving to the moon.

Another option is a 327 with 6" rods- it'll be more rev friendly, though make less power.

eric32 03-12-2009 03:45 PM

Well I will throw my two cents in here. What ever you do make sure your going with the right cam and don't over cam it. It takes everything to work together to make a good running motor. Compression, cam, heads,carb,intake,balancing of the rotating assembly, right stall range with automatic transmission and other things. Also having a good ignition system also helps out as well. Don't go cheap on stuff if you don't really have too be don't go overboard. If you don't want to spend a whole lot of money the look around for some good deal on cylinder heads. For just around $900.00 bucks you can get a set of world product heads assembled or for a little more Dart Platinum cast iron heads that comes with springs that can handle over 500 plus lift and would work good with your cam along the lines with a edelbrock rpm performer dual plain intake manifold. The rpm performer will give you better results on bottom end and for street use then the victor jr cause its more for midrange and top end. I used to use a victor intake on my engine build and I did not like it for street use and went to an edelbrock rpm performer air gap and it makes a difference from taking off and still does good on the top end. I have a chevy 350 with 650 quickfuel double pump carb, edelbrock rpm air gap, comp xtreme energy 288hr roller cam dual plain intake with Dart 200cc ported iron eagle heads. My compression is a little low at 9.5 to one but I need to run on pump gas. I use a high performance HEI that is curved for performance. I am actually going to go with a smaller cam for my build this fall so it will run better and work better with my setup. Hope more people can help you out. If you use your old stuff and clean them up and such for 2000 bucks you can get a complete vortec package with heads intake and all. I just saw it in my new summitracing catalog.
Eric

upstand2 03-13-2009 12:53 PM

hmmmm. 3000lb car , forged pistons and crank , 4.56 gears. Sounds like a screamer itching for nitrous to me.
I'd say any head 185-215 and of course a little shot. I don't know how it would'nt run 11's or better.

automotive breath 03-13-2009 01:46 PM

We have run similar combinations for years, how much you have to spend on heads?

TiMeWaRp 03-13-2009 02:42 PM

Quote:

Originally Posted by automotive breath
We have run similar combinations for years, how much you have to spend on heads?

2k max, so that seems to leave plenty of choices.

automotive breath 03-13-2009 04:20 PM

I'd go with the AFR 180cc SBC eliminator street cylinder heads with 65cc
chambers. Get a set of Scat I beam rods with cap screws, balance the
assembly. Zero deck the block and use a 0.040" thick head gasket. Single
plane intake with a 750 holley. Target high 10's on the motor.

carsonGs 12-20-2012 08:10 PM

For a 355 the AFRs are hard to beat. First i would do the block work if your going .030 over or .040 over start there you can deside on heads and intake the AFRs are some of the best around if your going with small or mid sized cam 750 carb. is to big go 600cfm or 650. dont over do it.A 284 is the biggest cam you can go with out running stall good cam for low end power not a drag car nice idle with alil lope. Personally I would pick up a 3500 stall and run a 292 thats just me.Hope this is helpful. btw i think in order to get a 355 is to go .030 over not .040

1Gary 12-20-2012 11:53 PM

Quote:

Originally Posted by Jsup (Post 1092270)
Find three reputable engine builders and let them spec it.

Let me tell you a little story. A guy I know asked the same question. He took all the forum advice. When he got his car on the street, he had guys using "junkyard motors" beating him silly.

Just sayin. If you're going to do your research on the internet, double, triple check it.

This caught my eye.So what ya saying is there isn't any pro's on this forum??.

1Gary 12-21-2012 12:26 AM

Anytime I advise someone on how to mod a first gen SBC,in the back of my mind I have the thought I am telling a guy to spend his hard earned money on what is really old technology. That the LSx engines might be better investment.The LSx engines have been around now for 14 yrs and the core/donor engine pricing is dropping to make that part of it more affordable.The aftermarket as it produces more products and more items,the pricing is dropping on that too.

So how this ties into this thread is no,I'm not telling him about a 350,355,or 383.What I am suggesting is for him to find a low mileage crash donor LSx with a T56 and harvest the wiring harness and computer.


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