Team Chevelle banner
  • Hey everyone! Enter your ride HERE to be a part JULY's Ride of the Month Challenge!
1 - 20 of 30 Posts

·
Registered
Joined
·
1,218 Posts
Discussion Starter · #1 ·
Hey everyone,

I've posted here before about my motor, and how it's lacking top end power. It has 400 882 heads. The bottom end of the motor is pretty stout, and the cam is a decent size, but I don't know the specs. All I know it's mild with about -13 vacuum at idle 850 RPMs. Would it be feasible to just change the heads to grab some power?

If so, what heads would you guys recommend? I'm looking for some pre fabbed heads that I can drop on and go. Can I keep my current lifters and push rods if I'm keeping the same cam? Does anyone have detailed instructions on how to change out the heads? I've never done it before, but I'd be willing to give it a try.

I daily the car, and drive about 5k miles per year.

Thanks!
 

·
Premium Member
Joined
·
2,693 Posts
It would probably be nice to know the cam specs before you buy new heads.
Different heads will like different cam's and having them matched will help to improve performance.
As has been said on here many times a matched combo will make a world of difference.
If you do go ahead and buy new heads a pushrod checker should be used and then you will know exactly what length pushrods are required.
As for bolting on a new set of heads without checking them it can be done but is not recommended.
Here is a link you may find helpful;




http://www.chevelles.com/forums/18-engine/943665-new-aluminum-heads-need-checked.html
Guy
 

·
Registered
Joined
·
1,218 Posts
Discussion Starter · #3 ·
It would probably be nice to know the cam specs before you buy new heads.
Different heads will like different cam's and having them matched will help to improve performance.
As has been said on here many times a matched combo will make a world of difference.
If you do go ahead and buy new heads a pushrod checker should be used and then you will know exactly what length pushrods are required.
As for bolting on a new set of heads without checking them it can be done but is not recommended.
Here is a link you may find helpful;

http://www.chevelles.com/forums/18-engine/943665-new-aluminum-heads-need-checked.html
Guy
I had a feeling someone would say this. I totally agree, knowing the cam specs will help me with better performance down the road. Thanks for the link!
 

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
8,729 Posts
Hi, I really don't know the answer to your question but you might get more great answers in the "engine" area, there's a lot more general engine discussion over there, when I was a kid in the 70's everybody wanted the camel hump heads for compression but that's a long time ago maybe better/newer stuff around
 

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
8,729 Posts
Oh and they had bigger valves and better flow
 

·
Premium Member
Joined
·
2,693 Posts
This might be a good time to plan things out and get a new cam to go along with new heads.
I'm on my second custom grind solid roller and have been very pleased with the results both times.
IMO,it's the only way to go.
Mike "Wolfplace" Lewis can help with heads and camshaft selection,he has helped me out a couple of times and knows his stuff;
Lewis Racing Engines
Guy
 

·
Registered
Joined
·
270 Posts
Not knowing cam specs. IF it was must just to put heads on. Just wanting it to run little harder an not get every ounce of power out of it. I would go on small side for that cubic inch. Like 64 cc an 200cc flow.
 

·
Registered
Joined
·
806 Posts
Not knowing cam specs. IF it was must just to put heads on. Just wanting it to run little harder an not get every ounce of power out of it. I would go on small side for that cubic inch. Like 64 cc an 200cc flow.
200cc heads are on the small side? Huh?



Op if it were me and you didn't want to mess with replacing the cam... Not that it's impossible to replace, but my guess is if you have never change heads before I would gamble that swapping a cam over will be a bit over your head at this point. I would find a head in the 170-180cc range maybe even a Vortec head. Your lifters and pushrods should work. Still doesn't hurt to verify valve contact area but I think you would be ok with re using them.

As for "how" to do it? Well there are many Chilton manuals and similar, meI prefer Mitchell or Motor manuals that use to be available at the local library or even doing a Google search for the step by step instructions on replacing heads. You don't need a "performance" driven manual per se as a head is a head on a small block. Where the areas are that will get you into trouble are making absolutely sure everything is clean & head surface is flat. That you use the right parts & gaskets. You know how to check all of your work and adjust the valves properly. Do you have the right tools? (THAT is one of the biggest headaches is not having the right tools) Torque wrenches, timing light, gasket cleaners wrenches, sockets, etc... I've got over 20K in tools to make my job easy as hell. (Snap On guy loves me ;) ) The kid down the street who has nothing as far as tools goes... is always asking to borrow something to help him out of a jam.

It's not rocket science and if you take your time and double check your work & use the right parts, you should be fine.
 

·
Registered
Joined
·
1,138 Posts
Op if it were me and you didn't want to mess with replacing the cam... Not that it's impossible to replace, but my guess is if you have never change heads before I would gamble that swapping a cam over will be a bit over your head at this point. I would find a head in the 170-180cc range maybe even a Vortec head. Your lifters and pushrods should work. Still doesn't hurt to verify valve contact area but I think you would be ok with re using them.
I agree on 170-180cc with an unknown cam. Will you be leaving some power on table? Probably, but who knows since cam/compression are unknowns. It's your first head swap.

I'd go with a set of Edelbrock heads. They're a known quantity, good quality, and will be markedly better than 882s. I wouldn't do Vortecs in this case, since it would also require a new intake and new valve covers. Sometimes things like throttle cable brackets or trans kickdown cable brackets use the intake bolt holes so that would require a little bit of re-engineering too. KISS principle here.

-Dave
 
  • Like
Reactions: blue_69_malibu

·
Registered
Joined
·
806 Posts
Only reason I went conservative on the head pick was his comments that his cam sounded "mild". If it were me I'd be getting something in the 185cc range.

882 heads are in the 150cc range with 76cc chambers. Probably the worst head possible to have ever been used for performance. Going to a 64cc chamber should give a decent bump in compression assuming flat top pistons. It all depends on what's in there now.

I only thought Vortecs if he was wanting to get a package deal from any of the various parts sellers. With those 882's who knows what intake he has. Everybody feels they have a bigger cam than what's reality. ;)
 

·
Registered
Joined
·
270 Posts
Sounds like we are on same page for most part. Within 15cc of each other. Considering we are not certain on any facts about rest of combo. Who knows? Few simple details could swing it either way.
 

·
Registered
Joined
·
1,218 Posts
Discussion Starter · #13 ·
Thanks for the advice guys! What do you think about the summit 185 heads?


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
806 Posts
The best way to help you is to list all that you have. What pistons you have? Are they flat top? Do you want to pay more for higher gas costs when going to an higher compression ratio? What gears do you have? What trans??? The list goes on and on... Try to list as much info as you can and be honest about what you want to do with this car.
 

·
Registered
Joined
·
5,422 Posts
I have cc'd some 882's and they are over 170cc I was amazed that they were larger than all smogger heads I measured not the 150 that was posted.
My bowl ported 186 heads measured 158cc. My ported 601 305 heads are 170cc Does not really make much difference as most smogger heads left stock flow really close to the same.

I ported a set of 993's with 1.94-1.50 valves for a friend he had a 350 and 270H comp cam.. really woke the thing up.
With the power gain he got with those 993's he got the bug and got greedy and figured a larger head aftermarket one would be even better he got the sportsman II 200cc runners 202-160 valves.

No gain at all.. it sounded different was all he noticed.
There are a lot of aftermarket heads out there and I tell my friends get the AFR Eliminator if you do not want to run a ported smogger.

With the sad performance of a early stock GM head (excluding vortec) you can't go wrong with most anything else.

I would contact one of the builders here and get heads from them.. that way you know they are right and ready vs getting from summit.

Or maybe it is time to get a book.
How to Build and Modify Chevrolet Small-Block V-8 Cylinder Heads (Motorbooks Workshop): David Vizard: 9780879385477: Amazon.com: Books

Excellent book, talks about porting etc and many pictures. :)
 

·
Registered
Joined
·
1,218 Posts
Discussion Starter · #16 ·
The best way to help you is to list all that you have. What pistons you have? Are they flat top? Do you want to pay more for higher gas costs when going to an higher compression ratio? What gears do you have? What trans??? The list goes on and on... Try to list as much info as you can and be honest about what you want to do with this car.


Well said. I was told they are flat top pistons. I don't mind running 91 octane here in CA. I have a 700r4 with 3:42 in the diff. I'm probably fine with the power output as it's a daily and don't need 500HP all the time, but really I'm just thinking of some different options to get some more top end power for those open road stretches. My car is built to handle 600HP. Trans , diff, radiator, fuel are all good for that number.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
806 Posts
Nice looking Chevelle!

I'm kinda in the same boat you are in. Wanting more power but not sure what cam I have in my 67 Chevelle. I have a set of 291 camel back heads but not sure what cam & pistons the bottom end has.

Switching to different heads to up my compression won't help much as I already have 64cc chambers. So I need more airflow. Only thing I know is my heads have been ported I just don't know how much they flow.

I recently bought a cheap $10 ebay borescope to insert into the spark plug hole to get a look at the pistons. Haven't gotten a chance yet to do it, may get to it Sunday afternoon.

I'd be asking the many experts here but I think you would be OK with what's been recommended already. The only thing that has me recommending a 185cc is your comment about the cam being "mild". But you also said it's "decent size"... Those are 2 different things that are throwing me off. If your cam is a bit bigger I would guess a 200cc head (as had been mentioned) would fit your need but if it's mild... see where this can go without knowing what you got?

Is there anyway you can get ahold of who built this and ask what cam they used?
 
1 - 20 of 30 Posts
Top