This message is to anyone to give me some help. I just abliterated the 305 TPI in my '86 IROC...seperated the damper...bent 2 pushrods...etc...and I just finished removing the motor from my car. Hard with TPI. Anyway, I've got a 2-bolt std.bore late model 350 I'm going to use to replace it. I've got a nodular-iron crank, GM rods, and I need to buy pistons. The block is a '95 and only had 10k when pulled for a spun bearing. The block is OK, but I don't have good heads...I heard 305 TPI heads were 58cc's in size, but haven't found a way to confirm this...I don't have much $$$ so I'd like to keep it cheap for now(I didn't expect to blow the motor). I need to know so I can buy some pistons. I found some hyperutectic pistons that advertize 8.4:1 W/76cc heads and 9.4:1 w/64cc heads...safe to assume 9.9-10.4:1 w/58cc heads? Has anyone done this swap? I have MAF(duh)and ordered a Crane 2040 Compucam, but with more compression I'm still worried about computer compatability(hypertech chip in car). I'd like to get some 'vette heads but don't have $$$. I'm still using the modded factory TPI(ported)setup, just to get me back on the road. I plan on a good set of aluminum heads, ZZ9 cam and a miniram in the future. Also, the 350 needs cam bearings, does anyone know how to change them without a special removal tool? Just a thought. Meanwhile I'll port the 305 heads and intake...
Word of advice...Don't abuse the red-line...I got a little too much of a good thing(which is now a bad thing...)Any help would be appreciated, thanks

 

Check the casting # on the top of the heads between the rocker-arm stud bosses. The last three digits of the casting number should be 416
If this is the case then you have the correct 86 High Output heads. These are the heads I use on my 305 (home ported) and will be super on your 350. The HO heads normally test around 57cc and could put you at 10.5:1 compression ratio if everything else is perfect. Real-world the compression will probably be closer to 10.0:1
You should have no problems with that. I would run a colder sparkplug for sure, and stay away from the platinum plugs. After that redline incident you may want to consider pressure checking or replacing your valvesprings too.
I think you will make great power with those heads on your 350. It is a very common swap on the street and on oval tracks (dirt) when the rules say Iron heads only.
good luck
ODB




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*I do custom performance mods on Edlebrock Performer carburetors (dualplane intake mods in the works),
White 1986 Irocz, 305 with iron #416 heads,
383 with aluminum TFS heads,
Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, Vigilante 2400 lockup converter, 3.25:1 Ford 9" rear, Mcreary Road-Stars, SLP-stainless 1.75" shortie headers & Y-pipe, single 3" Borla exhaust, Linginfelter-TPI camshaft part number 74216 pulls 17" vacuum solid. Cam specs 213/219 @.050 114-LSA, sometimes advertised at 216/219 @.050 112-LSA .462/.470 lift @1.5:1 ratio. Using Harland Sharp 1.65:1 roller rockers. MSD-6AL, billet distributor, multi-retard, blaster-3 coil, and RPM switch. SouthSide machine subframe connectors, SSM lift-bars, Moroso 4" underdrive crank pulley.

N/A runs 10.9 @124,
Crack-runs 10.3 @135
haven't run at track since Oct-99

[This message has been edited by The ODB (edited February 10, 2001).]

 

I'd say no. The 305 heads will choke your 350 engine worse than the TPI intake does... Find some cheap 350 heads. The 305 heads will work, however you wont make very good power with them, and the compression increase with iron heads might make you ping and knock and detonate too much.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Kevin,
I seriously hope you are not serious, especially if you are considering 107mph "good power".
Please let this guy go fast.

ODB

 

I just finished the heads. They have been ported, cleaned and appear OK. I haven't assemblled them yet, though. They are '416' heads...all valves and valveguides appear OK. Just removed all large obstructions in the intake tract. The heads are ready to be used, I'm just trying to make up my mind on parts...this will be temporary though, since the heads and intake will be replaced soon...I'm just trying to get up and running, and go a little faster while I'm at it. I'm using all the little tricks I know of.

 

Those heads will work fine for the time being.

 

in case anybody cares here are the flow numbers for the intake on those 416's

.100- 79
.200- 135
.300- 170
.400- 182
.500- 185

Those numbers are better than L98's up to .400 lift and after that there not even down 10 cfm from the L98's. So I'm sure with some mild porting they should work out pretty good.

 

Check my sig, I plan on upgrading in the future to, but for now I am running with 305 heads. I have ran around 13.9x-14.2x@94.XXmph depending on track conditions and my launches. So its not the worst thing to do, besides you can always save the money now and wait and buy a really good set of heads later with your mini ram.

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86 Trans Am 355 TPI Rebuilt 700R4 with Corvette servo, modified valve body, and a B&M Torque Converter (2000 rpm stall w/ lock up), 87 350 block bored .30 with new crank, bearings, rings, and magnafluxed rods. Reworked 305 heads with 3-angle valve job. Added in the rebuild was an SLP TPI cam, BBK 58mm Throttle Body,SVO 24# injectors,MSD 6A, Hypertech Power Coil, 1.5 Crane roller tipped rocker arms, SLP Intake Runners and Port matching in upper intake including fully ported plenum, TPIS adjustable fuel pressure regulator @ 46psi, Hooker shorty style headers w/ Thermotech heat wrapping, Custom 3” exhaust with Flowmaster muffler and chrome quad tips, Hypertech Thermomaster Computer chip, K&N open element cone filter on modified MAF per TPIS specs, MSD Wires, removal of A/C hardware and a 1LE firewall cover installed. Also there has been a PST front suspension kit with Hotchkis strut tower brace
http://geocities.com/SunsetStrip/Garage/9548/kyle.html

Kills:
95 Talon TSI, 96 Probe GT, 91 T/A L98, 89 RS, 86 Mustang GT, 88 Mustang LX 5.0, 92 Thunderbird V8. couple or ricers that I think were Civics or Preludes not sure what year, 95 Celica GT-S, 94 Chevy 1/4 ton 350, one of those NASCAR F150's ..... **** on Monkie
SOON TO BE A SUPER CHARGED TURBO WITH NOS ON A 500000 CU. IN engine

 

Snow, thank you for posting that info.
I do not have flow numbers on my own ported heads, but based on trapspeed mph gains I can say that there are major improvements to be had by porting in the bowl area.
Take down all the metal left from machining the bowls and as much as the valveguide boss as feasable.
Refer to your choice of several books describing smallblock chevy head porting. Or better yet, visit a performance engine builder and take a look at some ported heads there.

ODB

 

I used the same heads with 194,150 valves on my 383. They were fully ported and polished. Honestly they may have limited my motors potential, but they still flowed great. Use a -12cc dished piston and you'll be fine. With the right runners your tpi will be fine as far as flowing.

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Getty up my *** this ain't no damn pony ride!!!!
86 IROC 383tpi
The "bone stock" that rocks!