valve spring question

by rosco77 Fri Feb 03, 2017 9:04 pm

Hey guys. Haven't been on much due to life, but I'm gonna be building up a little 350 for the Malibu soon and need some advice. The block is from an early 70s Impala and has been sitting a while. It's also missing the heads. What we were going to do was get it bored .030 over and get new pistons and use a set of 305 heads I have on hand. I've been looking into to this and think it'll work well. I may port the heads down the road, but I'm not brave enough to try it right now. Anyhow, I'm wanting to upgrade the cam to this one from Summit https://www.summitracing.com/int/parts/sum-k00032/overview/make/chevrolet . It says in the description that valve springs are required. I didn't think this was a big enough cam for that. If there is nothing wrong with the stock springs, why won't those work? I'm an idiot when it comes to cams and need someone to dumb it down for me. No matter how much I read, it all still seems like greek.

by Joe73 Fri Feb 03, 2017 9:42 pm

Your stock springs with be fine with that lift. I think cm wl work well with a lower compression and your heads.

by rosco77 Fri Feb 03, 2017 9:46 pm

Cool. Thanks for the reply. I've been trying to read up on that for a week now. Lesson learned, ask sooner lol!

by fasrnur Fri Feb 03, 2017 10:34 pm

I also think your springs will be fine with that kind of lift. The 305 are smaller combustion chambers and will raise your comp. a 1/2 a point of so, but won't flow as good as most other small block heads. Just my opinion on that thought. The 305 heads have small valves and no room, if I remember right, to install larger valves. If not, here's a couple of choices on places to buy engine kits and springs. I have used them both over the years with great success.

http://www.northernautoparts.com/part/ek-ek1900#options

http://www.competitionproducts.com/Hi-Tech-Racing-Products-LT-1_Z-28-Chev-SB-Valve-Springs-1250-OD-120-1700-300-1250/productinfo/HTC2424/#.WJU74IWcE5s

by rosco77 Fri Feb 03, 2017 11:12 pm

Pretty cheap for those valve springs. Makes me consider doing it for "piece of mind." Thanks for the links. There's a rebuild kit I found on Summit. I'll have to compare the 2 a little closer when I get ready to order the parts.

I've read what you're talking about with the flow, that's why I mentioned a port job on the heads. There's some good information about the head swap on the 3rd gen camaro forum. The heads I have are the 601 casting which has about a 53cc chamber with 1.84/1.50 valves. It needs to be mentioned we're building this on a tight budget and not for all out performance. I want to car to be a fun cruiser with the guts to pass all these oil field trucks that run down the 2 lane blacktop around here.

by Joe73 Fri Feb 03, 2017 11:14 pm

Me personally, since your boring it and getting new pistons anyway. Get the right pistons for the compression you want. And have the block decked when its at the shop. Then use a head gasket that will give you a squished thickness of .040. If you dont get it decked, then go with a thinner head gasket. If you stay close to the .040 you will be happy and have a lesser chance of detonation to an extent.
And I would use the heads that came with your block. The 305 heads are great to boost the compression but kill flow. The engine is an air pump, the more air in the more air out. I ran in the 13s with 882, 76 cc heads with stock 1.94 valves.
Interesting video here about the 305 heads.
https://www.youtube.com/watch?v=0K1yGXct_sg

by fasrnur Fri Feb 03, 2017 11:36 pm

I agree with Joe. I personaly would look for a used pair of 350 heads. Make sure that you get the correct intake to match the heads. If you want to go with a good flowing head, you might look around for the "vortec" heads. They're plentiful these days and should be availble to be bought cheaply. Just make sure you get a intake for a "vortec" head. The center two bolts on both sides go straight up and down, and not at an angle. Also make sure you get valve covers for them too. They are center bolt covers. The "vortec" heads were, and are, a cheap way to get more flow for less money in my book.
I had a total of about $1800 in my last small block and it would have been cheaper if I hadn't put $500 into the heads. Screw in studs,dual springs, swirl polished valves, planed, and a valve job. A pair of heads and a good cam will do more for any engine than any other mod you can do in my opinion.
Here's a link for new valves.
http://www.competitionproducts.com/Stainless-Steel-Performance-Valve-Set-Chev-SB-11_32-Stem-1940-Int-1500-Exh-Set-of-16/productinfo/8430/#.WJVI6oWcE5s

I wish you luck on your project sir. I am in the same boat as you....budget budget budget. Very Happy

by rosco77 Fri Feb 03, 2017 11:50 pm

I've been looking for a used set, but haven't had much luck here. I might know where a set is, just not sure if they're any good. I've looked into the vortec heads, but like you said, I'll need a new intake. The engine I have already has an Edelbrock Performer sitting on top of it. The 305 has a spun bearing, otherwise I would just rebuild it for now, but when a free.99 350 block gets offered, I couldn't pass it up. A good friend has it and he was going to scrap it before I talked about building another motor for the Malibu.

by fasrnur Fri Feb 03, 2017 11:53 pm

Where are you located sir?

by rosco77 Fri Feb 03, 2017 11:54 pm

West Texas. Near Abilene

by fasrnur Sat Feb 04, 2017 12:02 am

Hears a website that has a few in Texas. Just put in the type of part you're looking for and follow the promps.
There are quite a few pairs of heads at what appear to be good prices. I just used a Monte for a model. It doesn't matter what you choose though.

http://www.car-part.com/

by fasrnur Sat Feb 04, 2017 12:04 am

I see you said something about a 99 block? Is that the year, or a casting number?

by rosco77 Sat Feb 04, 2017 12:07 am

Lol. No. Free.99. As in free dollars and 99 cents. Say it fast like you would 3.99, but it's free.99

by fasrnur Sat Feb 04, 2017 12:20 am

I like it rosc77. Just like my name here fasrnur. It's the plate on my car.

fasr n u r

Say it that way, and it makes since.

by bracketchev1221 Sat Feb 04, 2017 9:35 am

Find the heads first and build the short block around that. There is more performance in the cam and heads than in simple compression. So 10:1 compression and crappy cam and heads will not make as much power as a 8.5-9:1 engine with better heads and cam. This is why there are many pump gas high hp engines today.

by fasrnur Sat Feb 04, 2017 12:10 pm

So true bracketchev1211! There's really isn't a whole lot that has changed in the development to the rotating assembly over the years that truly make BIG power. The key is in the cam and heads. I myself have used Comp Cams Helpline http://www.compcams.com/Pages/360/support-information.aspx when I go to pick a cam. They are great to work with and it's their job to know what works in what engine combo you have. They will ask you quite a few questions about your car, so be prepared to answer them

Good luck rossco77.
Jeff

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