Team Chevelle banner
Cancel
Create thread New Garage Forums

840 Squart port heads,

Jump to Latest
1 - 20 of 56 Posts
B

bluechevelless

· Registered
Joined
·
1,358 Posts
Discussion starter · #1 ·
3919840....67-69...rect..CLOSED..396, 427, 107cc chamber

Anyone running these heads? I have a chance to get some that are gasket matched and cleaned up a bit for $400. Should I jump on them? Im running now with 101cc 215 oval ports with 9.7:1 compression 407 BBC
 
#2 ·
I personally would not run them on a 407" engine. The intake ports are too big IMHO. I ran a set on a 460" BBC with 11.5:1 compression, solid roller, Victor intake, Dominator. Went a best of 9.89@134 in a 3200lb backhalved Camaro. BUT, this was with a 5600 converter and 5.13 gears. I sold them about 12 years ago for $900. Might be worth buying to re-sell.
 
#3 ·
Even if you don't plan to use them, buy them. They usually sell for $1200 to $1600 on Ebay. I sold a set in less than a day for $1200. I'm running them on my 427 but as Jay said, they are a bit much for your combo.
James
 
#7 ·
those 215 casting heads are really good heads, basically the same port as a 781, or 049, but with a smaller 100-106cc chamber(depending on many variables)
I run a set of 290's which are identical to the 215's, on a 460" and really like em. with 2.19/1.88valves and a home bowl port they flowed 303cfm @28"water @ .650lift
I wouldnt put the square ports on your engine
 
Save
Reply Quote Like Like
#10 ·
if you use them, then it will cost you some compression. it will also cost you a lot of intake charge velocity (from the huge rectangle ports) VS. your ovals.thats way to much port for a 407.
you wont like it.
sounds like i'd better grab that set of 840's that my buddie offered me the other day though. might be some $$$ to be made.
 
#12 ·
Good luck Danny. JMHO, you are going backwards. Prior discussions and posts by you indicate the car runs poorly now as set-up (215 ovals, Torker 2-0 low rise single plane, 228-238@ .050 cam 114LSA, 2.56 gears). Now you are going to bolt on a set of ported rec ports? Those heads need 11/1 CR and 4.10 gears to work in a 396-402 motor getting spun to 6500 regularly.
 
#14 ·
GRN69CHV said:
Good luck Danny. JMHO, you are going backwards. Prior discussions and posts by you indicate the car runs poorly now as set-up (215 ovals, Torker 2-0 low rise single plane, 228-238@ .050 cam 114LSA, 2.56 gears). Now you are going to bolt on a set of ported rec ports? Those heads need 11/1 CR and 4.10 gears to work in a 396-402 motor getting spun to 6500 regularly.
Click to expand...
Amen to the 4.10 gears. I bought a new '70 Nova L-78 with TH400 and 3.55 gears. It wouldn't fall out of a tree (15.10 1/4 mile time) until I put headers and 4.10 gears in it. It eventually ran 12.84 with open headers and 7" cheater slicks. The best thing you could do for performance is sell the 840's for profit and install a Performer RPM or equivalent intake and change the gears to something in the 3.31 to 3.73 range.
 
Discussion starter · #15 ·
Gears are being bought soon, 3.42s or 3.55s are going in. Im trying to find a 5 speed overdrive trans but as of now the 400 will stay. Has a 3000 stall and 26" tires.
The cam I want is a hydraulic roller comp cams magnum, .566 lift, 280 advertised duration, 110 Lobe Center. Dual Plane Performer RPM will be going on also.

The car is my only car so it cant be down for long but what if I install the 840 heads and have the 215s cleaned up and gasket matched, maybe bigger valves installed then reinstall them later?
 
Discussion starter · #17 ·
I had 4.10s previously and my car was slow and couldnt do the highway. When I swapped to the 2.56s my car was actually faster and had alot more acceleration off the line. Hard to believe but the 2.56s helped my car.
 
#18 ·
GRN69CHV said:
Unless the 215's have some major issues, why bother to change them? I would not do anything esle prior to a gear swap. Going from a 2.56 to 3.55 will feel like you just added another 100HP.
Click to expand...
I agree 110%
Pick up the 840's and resell them a profit-PERIOD
take that cash and buy another of closed chamber heads and do them with the big valves,etc. or just go buy a 454

I vote to leave the motor as is for now..trust me,you'll be better off and the car will perform better.
 
#19 ·
How much do these heads flow unported (stock) at 6500RPM?

If I had these heads, an RPM air-gap, and open headers w/2 1/8 primaries and 4" collecter.......which of the three would be the limiting factor? What size carb would be needed to feed this monster at 5000' elevation?????

Don't mean to hi-jack...

thanks...
 
#20 ·
DieselEater said:
How much do these heads flow unported (stock) at 6500RPM?

If I had these heads, an RPM air-gap, and open headers w/2 1/8 primaries and 4" collecter.......which of the three would be the limiting factor? What size carb would be needed to feed this monster at 5000' elevation?????

Don't mean to hi-jack...

thanks...
Click to expand...
The dual plane.The 840,s and open exhaust = rpm.Go with a single plane and spacer,the dual plane will wheeze out over 6500 rpm.
 
1 - 20 of 56 Posts
About this Discussion
55 Replies
28 Participants
Last post:
dragginwagon406
Team Chevelle
posts
5.3M
members
131K
Since
1998
A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
Bench Racing Performance Engine Chevelle Tech Body Shop