wrong cam? or tune?



wrong cam? or tune?

Postby grumpyvette » February 1st, 2015, 1:06 pm

daytonajim00 wrote:I bought a re-manned 350 short block (.060 over) from my local machine shop about 9 months ago. I am no expert builder or cam match maker so I told them what I have and what I wanted.

I have a full size chevy truck and was wanting to make a daily driver with a little oomph. I have basic upgrades headers, ported cast heads, and a fresh quadrajet.

I asked for a mild cam maybe a step above stock.

I've put it all together and now 9 months later, am wondering about the cam after chasing problems randomly on my spare time as the truck sat.

I get around 14" of steady vacuum but suspect a vacuum leak and didn't think the engine was even idling on the idling circuit of the carb. That's when I checked the intake manifold mating surfaces and bought a new aluminum intake just to make sure. I also bought a freshly remanned quadrajet to match a 350 pre smog set up. I also recurved the distributor to make everything good ignition wise.

While on Chevytalk trying to get advice on spark plug selection advice for my set up (i searched and searched) someone raised concerns on the cam installed I thought of as "mild".

It's an Elgin 1227P. The cam card reads as giving a .450/.450 lift which IS mild BUT with a 232/232 duration. It's listed as a "lift rule" cam I guess for circle track racers under a certain lift requirement. That's fine but what does this specific cam mean as a daily driver like I requested on the mild side????

They are a reputable builder who have been around for decades. I know people make mistakes but the communication was clear and I am hoping it is in fact okay.

I've driven the truck maybe 200 miles but it ran poor. I will say, I haven't started it since the new carb and recurved dizzy. I will today. But, what is your guys take on that cam? I'm a complete noob to cam talk and am trying to learn by reading. PLease help though as I am kind of worried.

Tire Diameter: 35 Inches
Truck Weight: 4500lbs-5000lbslbs

I haven't dove into the gear ratios yet but I believe it was untouched and 2.73 was common. I know when building an engine all this must be considered so the engine builder took my specs and built what I thought was a pretty much standard short block.
1984 Chevy C-10:




Over caming an engine is a very common mistake, and that listed duration listed sounds like its quite a bit larger than I think would be ideal, for the application you listed.
first get the matching cam card listing specs, a 232 duration at .20 lift would more than likely be OK, the same .232 duration at .050 lift would be a bit too much in my opinion
Id like to see a good deal more info on compression and drive train, truck weight,tire diameter,gearing etc. before making a guess at the best match. but but ID bet something closer to this lunati or this crane would be a better match
http://www.cranecams.com/product/cart.p ... il&p=23790

http://www.summitracing.com/parts/lun-1 ... /overview/

http://catalog.elginind.com/app/engine_ ... by+Part+No. it looks like its at .050 lift
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viewtopic.php?f=52&t=82

viewtopic.php?f=71&t=741

why not call several cam manufacturers and get their tech department guys input as a reference, my guess is even the cams I suggested fall on the higher edge of the suggested duration and NOT A SINGLE ONE suggests something larger
[b]
take the time and effort to research the correct cam for the application, call at least 5 different cam manufacturers tech departments, I think you'll be surprised at what you find in the process

putting lipstick and hot pants on a pig , by trying to tune the engine to run so the mis matched components issues not as obvious, still doesn,t result in a cute super model, its just a band-aid approach to hiding a problem rather than a cure!

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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