I have an 86 coupe with 100,000 on it.I've been looking at heads and am curious.Its an 86E.If I got 113 heads will they fit my tpi?What aftermarket will fit.What are the changes I would have to make?I'm looking to go Superram new alum heads cam etc.I also see a few things for sale in the parts section I'd like to go with Mos90's roller block!This is my winter project So any info or advice would be helpful.I'm looking for about 350 or more to the rear wheels,while torque edging 400.Thanks!

 

I have an early 86, too which as you know came with iron heads. Those heads are not only heavy, but don't flow that well either.

When I decided to rebuild the stock 350 - several years back - I opted to go with Edelbrock Performer RPM aluminum heads. I'm still running them even though I've since switched to a 415 CID short block. Specs on those heads are on Edelbrocks website.

My thinking is the RPMs are a little too small in port size for a 415, but at present I'm stuck with using them. Edelbrock Victor Jrs would be a better match for my current combination.

I've but many thousands of miles on the RPMs as both a daily driver and all over the country on various interstates and haven't had a single problem with them. Based on my experience I HIGHLY RECOMMEND them. Cost of a complete set (ready to bolt on) is under $1000; I bought mine from Summit Racing.

There are many other aftermarket heads that will bolt right on too, just be sure to compare total cost, availablility, features and any quality control issues.

There are several sites that compare flow numbers among the various heads but such comparison do vary from site to site and are a can of worms to decipher. Remember, it's not just the actual flow numbers to consider but intake to exhaust flow ratio, mid-lift flow, intake port volume, spark plug angle, etc.

For example, you may find that the angle plug versions may not clear your exhaust manifolds/headers. I chose the straight plug version so the spark plugs would clear the TPIS long tube headers.

Just my thoughts.

Jake

 

Yes 113s will fit.
John Lingenfelter has the write up on what gaskets to use and such in his book.
I had planned doing this a while ago. If you end up doing it, let me know I still have the gaskets in plastic he recommends.


Jay 383, though he has a new name now, I can't remember what it is. Had the LPE 383 combo with ported heads in his 90? I think. Anyway, he ran something like 11.8's@120. So if you get well ported 113s thats awesome, otherwise maybe go aftermarket.

 

Thanks great info

 

Do you have a part number on the Edelbrock heads.So the tpi head angles didn't change from 85 to 91.For some reason I thought they canged after mid 86.Thanks

 

The center manifold bolt holes in both the manifold and the heads changed angle in the cast iron L98 heads as used in 1987 and up F bodied cars. When the Corvette went to aluminum heads (full time in 1987) the bolt hole angles stayed the same angles as from 1955 up.

RACE ON!!!

 

The heads I bought are 60739, which came complete, ready to bolt on. I opted for the better springs to be able to handle the higher lift camshaft I was going to install. No extra charge for those.

Jake

 

Thanks,Looked up the edelbrock heads and they are a great price!So my 86 cast iron heads are the same as 87 and up as far as the angles on the head to intake bolts.I want to use my TPI on 113 or aftermarket heads.Thats good to know!

 

Yep, they'll bolt right on. It would probably be a good idea to include a new set of ARP head bolts when you make the swap.

I used Fel Pro head gaskets and plenum/runner gaskets; NAPA, AutoZone, etc has them. I used Mr. Gasket Ultra Seals for the intake to head.


Jake

 

Thanks for the help.I'll be starting this pretty soon.

 

 

just remember that you are going from a 76 cc head to a 58 cc head, and your compression ratio will go to over 11:1. gas?

 

The Edelbrock 60739 Performer RPM heads I installed have 70 cc chambers.

Jake

 

11 to 1 is streetable.Right?It will also depend on my headgasket choice.So if aftermarket a 64cc would be ideal,Yielding about 10.5:1.I plan to go superram.What intake cc would be best for good HP and TQ.I was thinking anywhere from 180 to 195.With good mid flow numbers

 

Here's my thinking:

11:1 CR can be run on the street with the proper ignition and fuel maps burned in the PROM and with a cam having duration that's long enough. It'll probably call for Premium gas though.

As to whether 180/195 cc heads would be "right" for your combo; maybe/maybe not.

There are several variables involved in selecting the "right" intake port volume. CID, camshaft, rear end and trans gear ratios, engine RPM range, etc., just to name a few, must be factored in.

Selected parts should compliment each other. Many people tend to over-cam, over carburate/install injectors that are too large, run too much ignition timing, over-rev, etc. their engines. I guess the thinking is: "If a little is good and lot is better."

Be wise and choose complimentary parts.

Jake

 

 

I know exactly what you mean.I plan to run superram with a mild cam(Hopefully a roller)Haven't quite decided yet.I have 3.07's.I plan to drive it 4 days during the week.I would like it to do well at the strip also though.And fuel economy would be an issue.I don't want radical.Just a perfect combination of all that makes a quick street car.I would want torque more than HP.And nothing over 6000RPM.I hear a lot of people on here doing this.

 

If it were me, I'd select heads with port volume in the 170/180 cc range to keep the velocity up, thus improving throttle response crispness and off idle torque.

Larger port heads may make more power up top but you could lose response down low.

Jake

 

Thanks for giving helpful advice.I'm new to building a SBC and could probably use it.