Little Mouse

I agree changing to 1.6 won't be worth it. Your very low rpm engine is not pulling the secondaries even close to open all the way on a 750. Does not matter its feeding it all the air it needs.

Been there done that mistake on making 3310 open mechanicly in 1972 when the 3310 was rated at 780cfm back in 1972. Friend tried it first on his 350 Z/28 then i gave a whirl on the 302 Z/28. They make quicker opening DP carbs with " rear accel pumps " for a reason.

Tim H

it will either open or I'll put a screw in it and it will open!!!

Little Mouse

Thats what im telling you already done it with the screw back in 72 when i was younger and dumber.

I was reading a book by someone smart enough to write a book on holley. One thing he mentions don't do the screw thing. Where the hell were you in 72 lol.

As long as you have a light enough spring on the can it will open plenty fast enough and as far as the little 350 engine and low revs your at will pull it open.

You can pull all kinds of stunts get away with it if you use vacuum. My older cousin put a 950 holley three barrel on his 327/365hp 64 vette.

63mako

1.6 rockers do have their place but this is not it, don't think anyone suggested it. More lift won't help him because the heads won't flow more. More duration won't help him because it is overcammed as it is with his heads and compression. Your cam recommendation has more lift and duration and would be a useless waste of time and money. Best bang for the buck for the OP and you is a new set of good 64CC heads. The 882 heads are crap and severely limit the realized improvement from any other modifications. Heads make power. Flow makes power. Pretty basic.

srcuster

Look guys, I didn't mean to start a free for all. Gosh, I just needed a little advise. the story is, We (my husband and I) bought our 74 corvette new in 1974 (yes thats right, we are old). the car has always been in the garage and has 43000 original miles on it. Last summer Joe (my hubby) decided he wanted some more horsepower and wanted to change out old gaskets, put on new shocks and generally bring our vette back to it's original cluster. Our son has taken the tie arms, rods, transmission, and has sand blasted and repainted the parts and frame. It's looking really good. However, Joe is going to put new heads and cams on the engine. (Eldebrocks # 60899 cam and 7102 lifters) is what he is planning on putting on the original -82 engine. The car is a muncie 4 sp. He wants it to add about 110 to 120 more horsepower and keep the idle at 650 to 700 rpms. We wanted all your expert advice on if we are doing the right thing. Thanks to all of your for you help. Sheila

Tim H

So your telling 1000s and 1000s of people that taking a stock engine and change out the cam with a high performance one will not make any noticeable or useable power?
Nicely, I will say I disagree, because with just my current vette is basically a stock engine with a bigger cam and I guarantee my car has more power than stock even with factory heads.

63mako

My uncle had a Holley 3 BBL on his late 60's 427 Jet boat. Think it came that way.

63mako

That is totally not what I said. Re read my posts. Your L48 cam was under 200 duration. Changing it made a difference. A smaller split duration cam would have made more difference. The L82 cam is really too big. It was originally designed for the 1969 and 1970 11 to 1 350/350 HP with 64 CC 186 (fuelly) style heads and it was perfect for that, Those heads had decent flow and high compression. GM dropped the L82 to 9 to 1 compression and went with a 75 CC poorer flowing head and that cam was too big for the engine design. Your recommending more lift and duration yet. I am recommending better flowing heads and a compression increase by going 64cc and a thinner gasket to better use the cams capabilities. This goes for the OP and you as well.

63mako

If you want to add 110-120 HP and maintain good idle you are on the right track.
Go with AFR 64cc 180 heads
http://treperformance.com/i-61882-af...der-heads.html
Felpro 1094 gaskets and a roller cam something like this:
http://www.summitracing.com/parts/HRS-CL110245-12/
This intake.
http://www.summitracing.com/parts/EDL-2101/
Headers.
Performance distributor recurve.
This will get you what you want, maybe a little more.
It is not real cheap but 110 to 120 Hp upgrade while maintaining good idle and vacumn requires good flow without big ports and the 112 LSA roller will give you good vacumn and idle

Tim H

Yea!!!! its over, lets go on to something else.

scottyp99

LOL!!!!! This thread makes a lot more sense now..........


Keep the shiny side up!
Scott

63mako

If this is the cam your considering it will not idle smooth at 750 RPM. Way too big.
http://www.edelbrock.com/automotive_...7102&submit=go
And I am thinking your looking at this.
http://www.jegs.com/i/Edelbrock/350/2098/10002/-1
The combo I listed will get you what you want. The Edelbrock top end kit has too big of flat tappet cam and the intake won't fit under your hood. The operating range is to 6500 RPM. Your bottom end won't handle that. You will need to address gearing with that much duration. Not a good option. You will also want to change out the timing gears. It has the old nylon gear and it will be either bad or going to be bad once you get it back together with the added stresses a faster ramp cam will load it with.

Edit: I figured your static and dynamic compression with the parts I listed. Your at 10.26 to 1 compression and 8.11 to 1 DCR with an operating range of 1800 to 5400 RPM. This will get you <6000 RPM shift points and decent idle and vacumn. It will outperform the edelbrock package in HP and torque and have way better street manners!

cv67

Welcome to internet threads.

Page 1 usually get some useful info by p2 its all arguing and d1ckswinging
For some reason the Vette guys love to split hairs and go at it until they throw the mouse across the room. Daily


Listen to 63mako, billa etc. Couple others.


Btw he is right about the secondaries. If the motor doesnt need them open all the way thats all it needed in the first place. Opening them any further wont do jack.

billla

Mako's advice, as always is sound - and as he notes with all of those changes combined I think you'll more than hit your goals

I'd offer that with the existing cam, those heads (with all the other changes) would deliver around 375 HP. I couldn't find the cam card (just the base specs) on the Howard's cam, but I'd expect the cam to add another 30+ peak HP...and a good deal more TQ/HP throughout the range. Note that's with 1.6 rockers, and there are other changes required for a retrofit roller cam - so do your homework and set your budget.

I would recommend something a bit less rowdy, but as noted I tend towards the more conservative (read: cheap ) side of the house A set of Vortecs with the existing cam would put you in the 340 HP range at the flywheel, requiring only a head and intake swap. I would tend to keep the existing cam with the Vortecs - it's actually a decent match.

As a baseline, your L82 is probably making around 260 HP now (or less, based on state of tune) and would make around 300 or so with a dual-plane intake and headers/exhaust.

I would add that you should plan for a Q-Jet rebuild and tune to optimize for this new combo, or consider an aftermarket carb. If you plan to leave the car alone after these changes, and you plan to do them all at once, then I'd keep the Q-Jet. If you're planning on making the changes here and there over time, and may make changes later, consider an aftermarket carb. The rationale is that the Q-Jet is the greatest street carb of all time...but there are very few folks that can effectively tune it. Holleys are easy to tune and expertise and parts are readily available. Either way, budget for a dyno tune - without this, you're leaving power on the table for sure.

63mako

The existing cam is decent for most of your upgrades. One thing I would point out is you have put low miles on the car. Likely very few per year and as you said it has been parked for a long time. Need high zinc oil with your cam and the lift is not a good match for the real good heads. If I was tearing it down that far and wanted the idle, street manners and performance your looking for the roller is a $500 upgrade that meets your goals and will be a worry free option for years to come. I thing the operating range listed is conservative. I would think 1500 to 6000 is more likely with the 112 lsa with the biggest gains in the midrange of the curve.