push rod ???
Thread Starter
Cruising
Joined: Jul 2018
Posts: 11
Likes: 1
From: Panama city FL.
push rod ???
I am going to put the summit 355/400 hp top end kit on my 77 l-48 my ? is the heads in this kit look just like the performance 882's but with 2.02 and 1.60 valves 170 runners and 69 cc exhaust chambers and 62 cc combustion chambers the stock rods are 7.8 am i going to have to change rod lengths the new cam is a summit 1103 cam 214/224-444/466 close to the l-82 cam and the l-82 has 7.8 rods thanks in advance!
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If its a flat tappet cam, usually no, but with the new heads,if they are aluminum there is a possibilty that you will. I didnt have to with my Hekemian Racing heads but I dont know who made the Summit heads. If you look up there heads seperately and go to the questions and reviews, sometimes someone will post the same question. The only time I had to change my rods was with a rocker arm change to full rollers ( depends on the manufacturer) and when I went to a roller cam.
You should check them anyway and its pretty easy with the plugs out. Just put a thin layer of grease or magic marker on top of the valve and tighten up your rocker and rotate the engine over. THe rub mark left in the grease should be dead center or move from one side of center to the other. ITs kind of a pain to be so close to having it assembled and ready to go nd have to wait on rods. If you can borrow a pushrod measuring tool you should but you need to take off your springs and use a soft spring if you are rotating the engine over. If you are taking a static measurement you can just swap it in and try and get the rocker tip centered
good luck
You should check them anyway and its pretty easy with the plugs out. Just put a thin layer of grease or magic marker on top of the valve and tighten up your rocker and rotate the engine over. THe rub mark left in the grease should be dead center or move from one side of center to the other. ITs kind of a pain to be so close to having it assembled and ready to go nd have to wait on rods. If you can borrow a pushrod measuring tool you should but you need to take off your springs and use a soft spring if you are rotating the engine over. If you are taking a static measurement you can just swap it in and try and get the rocker tip centered
good luck
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
One thing that determines pushrod length is where the rocker arm pad or deck is compared to stock configuration. Several aluminum head companies have move the pad a little higher. Usually, but not always, a pushrod with + 0.100 longer is in order. Be prepared to pay almost $100 a set for one piece rods, hardened for guide plates.
And order top-notch head gaskets that are compatible for aluminum heads on cast iron block. $40 each!
Use top notch headbolts such as ARPs also. $125 set.
These are all "hidden fees" when switching to aluminum heads.
And order top-notch head gaskets that are compatible for aluminum heads on cast iron block. $40 each!
Use top notch headbolts such as ARPs also. $125 set.
These are all "hidden fees" when switching to aluminum heads.
Last edited by HeadsU.P.; Apr 4, 2020 at 09:12 AM.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
I've never seen a top end kit I liked because they're all a box of Compromises; including this one.
https://www.summitracing.com/parts/sme-k-355-400
states it includes a pushrod length checking tool.
its intake is made to fit squarebore carb only; not QuardraJet
kit installed as-is on OE 77 L48 should yield No More than 9.25:1 CR
https://www.summitracing.com/parts/sme-k-355-400
states it includes a pushrod length checking tool.
its intake is made to fit squarebore carb only; not QuardraJet
kit installed as-is on OE 77 L48 should yield No More than 9.25:1 CR
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Me thinks OP should spend a few more $ and improve his dished-piston L48 around a pair of TFS 175 DHC about $1400/pr
https://www.summitracing.com/parts/tfs-30210006
https://www.summitracing.com/parts/tfs-30210006
Thread Starter
Cruising
Joined: Jul 2018
Posts: 11
Likes: 1
From: Panama city FL.
I've never seen a top end kit I liked because they're all a box of Compromises; including this one.
https://www.summitracing.com/parts/sme-k-355-400
states it includes a pushrod length checking tool.
its intake is made to fit squarebore carb only; not QuardraJet
kit installed as-is on OE 77 L48 should yield No More than 9.25:1 CR
https://www.summitracing.com/parts/sme-k-355-400
states it includes a pushrod length checking tool.
its intake is made to fit squarebore carb only; not QuardraJet
kit installed as-is on OE 77 L48 should yield No More than 9.25:1 CR
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Thread Starter
Cruising
Joined: Jul 2018
Posts: 11
Likes: 1
From: Panama city FL.
If its a flat tappet cam, usually no, but with the new heads,if they are aluminum there is a possibilty that you will. I didnt have to with my Hekemian Racing heads but I dont know who made the Summit heads. If you look up there heads seperately and go to the questions and reviews, sometimes someone will post the same question. The only time I had to change my rods was with a rocker arm change to full rollers ( depends on the manufacturer) and when I went to a roller cam.
You should check them anyway and its pretty easy with the plugs out. Just put a thin layer of grease or magic marker on top of the valve and tighten up your rocker and rotate the engine over. THe rub mark left in the grease should be dead center or move from one side of center to the other. ITs kind of a pain to be so close to having it assembled and ready to go nd have to wait on rods. If you can borrow a pushrod measuring tool you should but you need to take off your springs and use a soft spring if you are rotating the engine over. If you are taking a static measurement you can just swap it in and try and get the rocker tip centered
good luck
You should check them anyway and its pretty easy with the plugs out. Just put a thin layer of grease or magic marker on top of the valve and tighten up your rocker and rotate the engine over. THe rub mark left in the grease should be dead center or move from one side of center to the other. ITs kind of a pain to be so close to having it assembled and ready to go nd have to wait on rods. If you can borrow a pushrod measuring tool you should but you need to take off your springs and use a soft spring if you are rotating the engine over. If you are taking a static measurement you can just swap it in and try and get the rocker tip centered
good luck
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
OP
regardless which or whose head ... Quench/Squish distance is Very important to an optimal combo. Your OE pistons are approx 0.025" below an OE deck. A widely accepted optimal quench distance for a street SBC is 0.040" ... these 0.015" shim gaskets (felpro 1094) are Ideal for use w/ either iron or aluminum.
https://www.summitracing.com/parts/fel-1094
fwiw ... word has it that Summit acquired TFS Trick Flow Specialties
There's nothing wrong w/ the head gaskets in the kit EXCEPT they are so thick at 0.041" they'll kill off quench benefits.
if your motor is OE, the summit heads + the shim gaskets will yield about 9.6:1 - 9.7:1 CR w/ perfect quench.
use that PR length checker & good luck
regardless which or whose head ... Quench/Squish distance is Very important to an optimal combo. Your OE pistons are approx 0.025" below an OE deck. A widely accepted optimal quench distance for a street SBC is 0.040" ... these 0.015" shim gaskets (felpro 1094) are Ideal for use w/ either iron or aluminum.
https://www.summitracing.com/parts/fel-1094
fwiw ... word has it that Summit acquired TFS Trick Flow Specialties
There's nothing wrong w/ the head gaskets in the kit EXCEPT they are so thick at 0.041" they'll kill off quench benefits.
if your motor is OE, the summit heads + the shim gaskets will yield about 9.6:1 - 9.7:1 CR w/ perfect quench.
use that PR length checker & good luck